Thursday, February 8, 2018

Third-graders at the farm


Third-graders from Tsukuba International School (TIS) came this year again
 to learn about renewable energy and solar sharing.

20 students and 7 teachers and parents on February 6, 2018

This was already third time that TIS students visited our farm.

This time, baby goats and chickens took all the spotlight, but that's just fine. As far as I remember, the purpose of school excursions was always (1) to have fun, (2) maybe to learn something. But the times may have changed since my school years, because the TIS children were (despite the baby goat distraction) curious and inquisitive, as they've always been on their visits to our farm, so we most probably managed to learn something together.

We talked about how the energy from sun turns into electricity when sunlight hits the panel surface, and how that electricity moves through the cables to inverters, then to the distribution box and finally up the utility pole to the public grid, so people can use the electricity in their homes. 

As all the things mentioned - the panels, the inverters, the utility pole - were right there on the farm in front of us, I hope the abstract concept of electricity became a little more concrete. 

We also checked out how much the electricity production changes when I change the tilt of the panels. (In February, the optimum angle in our area is 50 degrees. When we moved the tilt to the July position of about 4 degrees, electricity generation dropped by about 30%, which is a lot.) 
*We can check power generation status of the farm in the real time thanks to Solar monitor.

This year we didn't have much time to talk about the chickens (why we have chickens at the farm), but that's fine too. As long as the students had fun and remember the chickens, the goats, and the solar panels as they saw them on the farm, mission is completed. I can sleep well at night.

Sunday, January 28, 2018

Goat baby boom


As we already announced on our Japanese blog, Natchan the Queen gave birth to four healthy baby goats on January 19, 2018, or about a week ago.

Natchan and her day-old babies (2018/1/20)

It's three girls and a boy! (2018/1/20)

If Natchan's delivery is already old news, the new news is that five days later, on January 24th, another goat, Momochan, delivered too! She gave birth to a healthy girl.

Momochan and her baby girl (2018/1/25)

Momochan currently doesn't live on our farm. She has a private room in the home of Mrs. Yagishita, our Chief Goat Officer who lives a short walk from the farm. This is because Momochan has an inborn problem with front legs and is easily bullied if kept with other goats. Instead of walking straight, she prefers to walk with her front knees bent. Otherwise she's a healthy, mild tempered, sweet goat, but she's not exactly super-strong and we never expected her to get pregnant. However, now she's a good mum and her leg issue is clearly not a problem in fulfilling here mum duties.

Momochan in her preferred standing position.
(She can stand or walk straight if she wants.)

Moreover, the current situation brought about an additional benefit: the opportunity for "mum sharing". 

"Mum sharing"

Mum sharing means that babies share their mums.
Natchan gave birth to four babies, which is a little too many to support without human assistance. Goats have only two teats, so four babies have to compete who gets most milk.  

That's why Mrs. Yagishita would have to do some bottle feeding to make sure all four babies grow fine.

See the milk bottles?
But Momochan's new mum status created an opportunity for a better solution: We took the smallest of Natchan's four babies to Momochan to see if she would accept her. And Momochan said, okay, why not? She snuffed the new baby's bottom, it smelled good, so she let her suck. 
Momochan's baby girl now has a playmate!

As a result, Natchan is feeding three babies and Momochan is feeding two. 
In the meantime Yagishita san is busy procuring enough food both Natchan and Momochan. This is not easy in winter.

If you are worried that Natchan or the baby might have suffered emotional damage from being separated, I can assure you that this is not the case. Natchan hardly noticed one baby is missing, and the baby was happy to be with her new mum as soon as she was allowed to suck. (It's easy to identify a goat in distress. There was none this time.)

Natchan and three babies (2018/1/27)

We will keep you posted about new developments.

Sunday, January 21, 2018

Our farm introduced in The Japan Agricultural News

Chickens' Playground was introduced in The Japan Agricultural News (日本農業新聞)on January 18, 2018.

Click to enlarge

For my commentary (and corrections to the article), please read this blog entry in Japanese.

Monday, January 8, 2018

Happy New Year! ...and what next. (About the future of the farm)

"Happy New Year!" chickens and goats must have said, but we missed it because our Chickenspeak and Goatspeak are still poor.

Happy New Year from a Chicken

Happy New Year from a Goat

It's a Year of Dog.

Happy Dog Year, Japanese New Year Cards
Here are some of the New Year postcards we got!

Because it's a Year of Dog, our chickens quickly decided to forget that Chinese Zodiac ever existed. (They liked Chinese Zodiac last year. It was a Year of Rooster.)

Chickens' Playground, Power Plant Oo, Tsukuba, Japan

Chicken and New Dog Year postcards

Chickens and New Dog Year postcards

Now some important updates about the farm.

There are now 11 chickens and 3 goats on the farm. The number of goats is pretty stable, but the number of chickens dropped to one third of the original flock. This is because we killed and ate them. We did our best to take their life quickly, and we didn't waste anything as we turned them into food.

Killing our chickens is never fun and I'm relieved we don't have to do it again for at least the next few months. With the last eleven chickens left, their "pet" status naturally grew stronger. To put it another way, their "farm animal" status has become a little untenable. We should have expected it: as there are fewer animals, their personalities stand out more and it's harder to subscribe to the pet-is-friend-but-farm-animal-is-machine doublethink. (That's why big industrial farms with tens of thousands of animals are the perfect design to make us numb.)

After selling eggs for more than two years, we stopped last autumn, or about two months ago.
Chickens still lay a few eggs a day, just enough for our personal consumption and sharing with neighbors.

The question is, what next.  

At first this may seem like the end of the Chickens' Playground, but we'd like to think of it as a creative break.

Here's the thing:
We really want to continue the farm. Of all the chicken farms I've visited in Japan, our chickens have by far the best living conditions and the highest degree of relative freedom where they can express all of their original behaviors including their foraging habits (unfortunately, large outdoor runs like ours are now extremely rare on commercial chicken farms in Japan. Reason: they require more space, more spending on fencing and more risk management tasks for the farmer, including unavoidable contact of chickens with wild birds = potential disease-carriers.) If I eat eggs, I want them to be from a farm like ours. But there is no other farm like ours. That's why we have to make our farm work.

But it's not that simple. There is a reason why there is no other farm like ours - because it is not economically sustainable.

Despite having a lot of loyal customers who paid three times the usual price for our hens' eggs and had to put up with the inconvenience of coming to pick them up to the farm, for which support we will love our customers forever, the farm was still relying on - mostly my - volunteer labor, which may work for a year or two, but it's not feasible in the long term. Especially now that I lost control over much of my time by switching from a freelancer to a regular 9-5 job, running the farm in the same way we did for the past two years is impossible.

We also can't rely on the income from the solar panels as much as we'd like to. Not only the equipment for chickens costs more than we had thought. Because we built the farm using our savings and a loan, using the income from electricity to subsidize the farm is like paying for the farm from our savings - you can't afford that unless you're a millionaire.

All in all, the scale of the farm - just 30+ chickens - is too small to make it pay for all the costs, including our time. This is an undeniable fact. But increasing the number of chickens is not the answer. It would only lead to the same compromises (both environmental and animal welfare) that we have seen on all the other farms.

But we believe there are ways how to fix this.  First of all, we need to improve the design of the farm to make things a little more efficient and a little less time-demanding. But we have to do it in a smart way that doesn't impact the chickens.

Personally, I'm a big fan of efficiency. If I can finish a boring or grueling task quickly or easily using a smart tool, I will. I can then use the saved time to read a book. But I'm not a fan of ill-defined "efficiency" in farming, where it often means more pesticides and chemical fertilizers in exchange for a little higher yield, while all the negative environmental costs (like destruction of ecosystems) are externalized.  In case of animal farming, more "efficiency" usually means less space and worse conditions for animals. Battery cage is undoubtedly the most "efficient" way of producing eggs, but that doesn't mean it is the right way. A practice that would be labeled animal abuse if it was done to a companion animal,  should not be applied to farm animals either.

So there's real efficiency and pseudo efficiency, and it's important to see the difference. On our farm, we're pursuing the former - there are still many things to improve that have nothing to do with environmental costs or animal welfare. However, these improvements require either time (to figure out what works best through trial-and-error) or money (to buy or build the better designed thing) or, usually, both.

Example: We have a huge problem with sparrows who come in crowds to eat chickens' feed and to sh*t everywhere. They sh*t into chickens' drinking water and on the solar panels. I'm not overstating: the future of our farm depends on solving the sparrow curse.
The easiest solution would be shutting the chickens inside the coop, thus cutting sparrows' access to the feed. Eventually they would realize that there are no free meals any more and would stop coming altogether. However, shutting chickens in the coop means denying them access to the outdoor run, so it's not exactly a chicken-friendly solution. We asked the chickens and they (obviously) said they didn't like the idea, so we have to figure out something smarter. The solution is out there, we just have to find it. For example, building a smart feeder that only chickens could open, but not sparrows. Chickens would have free access to their meals and to their run, but there would be no free food for the sparrows. This would save us a lot of time and money.
Something like this (the video below is not from our farm):

This was just one example how better design could help us solve many of the issues that we ran into in the past two years. In that sense, the past two years were an important Stage 1 of this long term project: a learning phase that allowed us to notice what practical problems there are. Now we can start ironing them out.

That's why we'd like to call this a Phase 2: Creative break!

My genius idea is just about to pop up.
"My genius idea is just about to pop up."

Sunday, September 17, 2017

Why a fence for chickens won't work for goats (and vice versa)?

For the sake of our beloved chickens and goats, we are repairing the fence. We're still half-way, but here's a report anyway.

Drilling holes for new wood posts...

... hammering posts into the ground ...
... attaching wire mesh to the posts...
... and finally attaching wood planks over the mesh.

 Repeat on the next part of the fence.

The goal is to make the old fence both chicken and goat proof.

Chicken proof and goat proof are two very different things, as we learned after two years of experience with chicken & goat cohabitation.
Now we know what a perfect fence for both should look like.

Chicken proof and goat proof fence.
(That duck in the middle, that's wild.)

So why a fence for chickens won't work for goats and vice versa?

Because chickens are little flying birds while goats are big mammals with hoofs and horns.
Neither chickens nor goats have any respect for human-set boundaries (why should they?), but their ways of crossing the boundaries are completely different.

Fence and Chickens

With our old fence being just 1 meter high, smarter chickens easily flew over it. It wasn't okay, but somewhere deep inside we thought it was freespirited, funny and cute. Until some of the rice farmers around started spraying chemical weed killers on the slopes of their rice fields (where the runaway chickens liked to play). And - that was the final straw - until one chicken was hit by a car (she died instantly). The driver didn't even attempt to slow down. Clearly, not everyone thinks a free ranging chicken is funny or cute.

For a fence to really protect chickens from outside enemies like this, it should be more than 2 meters high, so part of the current repair process is making the fence higher. We're making it about 1.8 meters high, which is less than the ideal 2 meters, but still a substantial and hopefully sufficient upgrade of chickens' safety.

By the way, our chickens' run, to which they have unrestricted access all the time, has an area of about 580 square meters, which I'm confident is big enough to keep them happy, without the need to fly out and play on the road.

Fence and Goats

The old fence - made of simple wire mesh attached to a few wooden posts - was bound to give in to the goats.
In defense of goats, their intent was never destructive, it's just that they like doing all things anti-fence:
1. rubbing their backs against wire mesh. This clearly give goats great pleasure. Unsurprisingly, after a while posts start to lean and mesh to tear.
2. fiddling with the fence with their horns. This must be so fun! It's also the best way how to tear up the mesh, making holes in it (through which then chickens can escape).
3. using the mesh as a step to reach for things over the fence. Like this:

Natchan reaching for her favorite shrub over the fence.

The same scene from the opposite side.
You can see her hoof on the mesh.

In order to make the fence goat proof, it's necessary to
1. use more and thicker posts to support the fence.
2. attach wood planks over the mesh so it can withstand goat pressure.
These two things are now a part of the repair process.

This is how we've been spending many of our no-rain weekends and some weekdays for the past one and a half months. I wrote this blog today only because it's raining.

God bless chickens and goats for keeping us busy.
(In fact chickens think I'm the god.) (Goats are atheists.)

Sunday, July 30, 2017

What is a "quality" egg

Our chickens are now two years and three months old and this affects both the quantity and the quality of the eggs they lay.
Chicken in clover: So what.
Exactly. (But some people seem bothered.)
In this post I'll explain one specific "quality" issue related to hens' age - something that most people don't know about.

When we talk eggs, we usually have in mind several indicators to tell us how fresh and/or how good quality an egg is. We look whether  the shell is strong and hard to break, whether the yolk is firm and has the 'right' color (whatever that means) and whether the white is thick and upstanding.

These may look like pretty commonsense rules, but at least that part about egg white - that's only half of the story. The other half is worth knowing too, especially  if you buy eggs from a small farm where chickens might live longer than commercial layers on large, industrial style farms.

Egg white

We usually consider it an indicator of freshness.

Last Judgment, egg version

That's what egg industry tells us and what we, consumers, believe. And in general it's true - a firm, thick egg white is usually a sign of fresh egg.

Except, it’s not always true.

That’s what I learned from our chickens, who are now far beyond the working age of laying hens in the "modern" egg industry, where hens are normally disposed of at 17-18 months of age. Ours are 27 months old and about to announce their retirement, but at the moment they still lay eggs, which we still sell, although only to the last few most understanding customers who care about the chickens as much as about the eggs.

So here's the thing about the egg white, the fancy word for which is albumen.

Egg albumen introducing himself with a big smile. Yolk does nothing.
There are two types of albumen in every egg: thick and thin
In this article we're talking about thick albumen.

Albumen is typically thick and upstanding when the egg is freshly laid, but becomes thinner as days pass, especially if you store eggs in a warm and humid place, or in a place where temperature frequently changes.

Albumen height

Albumen height is considered such an important indicator that in the egg industry and egg science, it is measured with a tripod micrometer and used as a basis for calculating Haugh unit - a ubiquitous measure of egg freshness since it was invented in 1937.

Less known is the fact that as hens grow older, their eggs' albumen height naturally decreases. It is a normal change - a result of hens' reproduction organs aging.

In case of our flock, the differences are also quite individual – some hens still lay eggs with firm egg whites, others not so. All hens are exactly the same age, live in the same environment, eat the same diet and are all healthy – so the difference can only be attributed to individual genetic makeup.
Also, our hens are not really "old" yet. With a natural life span of 8-10 years, a two-years-and-three-months-old hen (our flock) is not that much older than a one-and-a-half-year-old hen (slaughter age of laying hens).
As for those eggs with lower albumen height, everything else is just fine - the egg looks fine, the shell is strong and the yolk is firm. It’s just the egg white getting flatter. Despite it being a natural consequence of the hen's age and genes, this egg, even though it's fresh, would be considered by ordinary consumer as old and of lower quality.

if a healthy hen lays a pretty, perfectly edible egg whose only fault is thinner egg whiteis that really a quality issue, or is it just a man-made fussiness? 
I wondered.

If it is a real quality issue, low albumen height surely must be a sign of some other profound defect. It can't be just the fact that the egg spreads too much on a frying pan for your sunny side up, right? Two hypothesis come to mind. 

Hypothesis 1: Maybe low albumen height is a sign of fewer nutrients. Like, less vitamins or minerals in the egg?
I checked it out and the answer is: Nope, it seems that albumen height has nothing to do with nutritional content. This conclusion is based (besides common sense) on the fact that I simply could not find any evidence - no data, no scientific studies, no observations or even a discussion - about the relationship between albumen height (or Haugh unit) and nutritional value of eggs. Given how much and how thoroughly eggs have been studied and tested and researched around the world for decades, the fact that there is no information at all on this topic seems like a reliable proof that there is no such relationship. The closest I could find was this study of partridge eggs, which found that "[t]here is no effect of the storage time on the mineral content of the egg." [1] 

Hypothesis 2: Maybe low albumen height means that you can’t whip it into good foam? That would be real functional deficiency for both processing industry and individual consumers who like baking.
So I checked it out and the answer is: Nope, lower albumen height does not cause lower whipping volume. In fact, it causes higher whipping volume, as practical experience and this study shows. So you get more whipping foam out of less firm albumen. [2]
In other words, we have two egg quality criteria - albumen height and whipping volume - that contradict each other. SO SMART.

So now we know that low albumen height is not a sign of some deeper quality problem. It's rather a human-invented aesthetic function of fried eggs with about as much substance to it as saying that a big apple is of higher quality than a small apple, because ... because.


But at least it is an indicator of freshness, right?

Well, no. I already mentioned that albumen height decreases with hens' age, and that there are individual differences between hens. This is not just personal observation, it's what research, such as the study mentioned above, shows: although it is true that albumen height decreases with storage, it is also a heritable trait and is biased by the age and strain of hen, therefore it is not a reliable indicator of freshness. By the way, a better indicator of freshness would be albumen pH, which "is determined almost entirely by storage time and may be more useful than albumen height for measuring egg quality." [2]

To sum it up, when an egg has thin egg white, it can be either because the egg is old, or because the hen is "old" or because the hen inherited the trait from her parents.

Most people don't know this because they don't keep backyard flocks anymore and the egg industry has only been telling us the first part of the story - that albumen height decreases with storage.

What does it mean for hens?

For hens it means that they are killed too soon.

Of course, both quality and quantity of eggs goes down by the time hens are 17-months old. By then, a flock of 100 hens would lay about 65 - 70 eggs a day, as compared to more than 90 eggs/day during peak lay period. That's the quantity part. As for quality, the major issue with older hens is thinner egg white explained above.

Whether you interpret the 65-70 eggs as too many or too few as a threshold for culling the whole flock - that's a matter of opinion. Speaking for myself, killing the entire flock of healthy hens when they could still produce every day 65 - 70 perfectly okay eggs, whose only fault would be slightly thinner egg white, sounds like a terrible disregard for animal life. You certainly wouldn't kill all chickens at that point if they were your own backyard flock.

The problem with "modern" farming is that the value of an animal is inversely proportionate to the number of animals, in other words, the more animals you have, the less important an individual animal is. Large farms with tens of thousands of chickens simply get them on the truck and send them to the slaughter house. This is much different on our "farm" with less than two dozens of chickens.  We marvel every day how cute they are (although the rooster can be an as*hole) and then we kill them ourselves. I know it's unavoidable, but frankly, killing a chicken is not exactly a pleasant thing to do, especially not for the chicken. We want to reduce the frequency of slaughter sessions to minimum and so far we were able to do exactly that thanks to our customers who stayed with us and kept buying the eggs despite chickens' age.
Of course, our customers are special and I know I can't expect the same compassion and generosity from everyone.

But I still imagine how nice it would be if more people in the world were able to, both metaphorically and literally, see the hen behind the egg, as our customers can, and decide what is more important to them - a thick egg white that only young hens can produce, or a hen that had happy and (relatively) long life that she deserves, even if, towards the end, the egg white is not quite as thick as the egg industry has been telling us it should be.

Wanna know my opinion?
Oh, and I almost forgot. I guess you'd like to see what our hens' eggs actually look like. Here are four randomly chosen eggs from today morning. These eggs were laid by 2-years-and-3-months-old hens.

Actually, they look quite okay, don't they?

External links
Günhan S., Kirikçi K. 2017 Effects of different storage time on hatching results and some egg quality characteristics of rock partridge (A. graeca) (management and production). [Abstract]
Silversides F. G., Budgell K. 2004 The Relationships Among Measures of Egg Albumen Height, pH, and Whipping Volume. [Full text]

Tuesday, July 11, 2017

Chickens and goats in the jungle


As summer arrived, chickens, goats and weeds keep us busy (so much for the excuse why there was no blog update for almost two months.) With the start of rainy season, chickens' playground - or, as chickens prefer to call it, Chickens' Republic - again turned into jungle.

Jungle is welcome because it keeps chickens in shade and (somewhat) cool(er). They would have much, much harder time without all the greenery around. But at some point, jungle becomes a bit of a nuisance - too many, too big weed trees are inconvenient even for the chickens.

Translation from Chickenspeak:
"Where are you, darling, I can hear you but I can't see you..."

So we decided it's time to step in and ask the goats for help. Three inhabitants of the neighboring Goat Kingdom kindly accepted our invitation.

Natchan the Boss on the Mission Unjungle

Goats' weeding strategy is to get the most delicious top leaves first:

But interspecies coexistence usually comes with challenges. In our case, there are exactly two:

Challenge 1: Goats love chickens' feed.

Goats' access to chicken run means access to chicken coop, where our hens and a rooster get their daily meals, which contain a lot of stuff that goats love too, like wheat, corn and okara. This is what happens then:

"Hello! ...Oh, yes it was delicious, thanks for asking."
(Natchan just finished her chicken meal.)

But we can't let goats eat chickens' food because, 1) we don't want chickens to be hungry, both because they don't like to be hungry and because their diet directly affects the quality of eggs,  2) chickens' feed also contains small amount of ingredients that goats shouldn't really eat, like oyster shells and fish powder. And we don't want goats to upset their delicate stomachs.

So the challenge is: how to allow goats to the chickens' playground while not allowing them into chickens' dining room, all at the same time  as chickens have free access to both.
The challenge was resolved by an old trick where you build a fence that goats can't cross, but you leave space at the bottom that only chickens can pass through.

Here's a chicken just passing through under the fence.

This sounds like an easy solution but getting the height of the bottom open space just right can be tricky - leave it too low and chickens will have hard time passing through (especially the rooster), leave it too high and a small crawling goat like Momochan will pass as well and head straight to the forbidden area.

Momochan and the chickens.

Momochan and the chickens, from different angle.

We are still working on this. Goat visits to chickens' coop are, um, not so frequent.

Challenge 2: Goats love cultivated plants as much as wild ones. 

On January 3, 2016 - a year and a half ago - we foolishly planted three persimmon trees in the chicken run, hoping that one day they would grow big and provide chickens nice shade in the summer (we didn't know yet that the naturally occurring weed trees would provide the same service free of our labor.)

January 3, 2016: Baby persimmons!

Arrows show where the baby trees were planted.

These three persimmon trees have since endured multiple goat attacks. They were repeatedly reduced to leafless sticks and the very fact that they survived is quite amazing. We've built about five different versions of protective anti-goat fence but every time it turned out we were too naive about Natchan's  ability to tear down every obstacle between her and those freshly grown young juicy persimmon leaves. BUT NOW, we said Enough is enough. Version 5.5 of anti-goat protective enclosure is unbreakable (until goat hackers come up with something new).

Nobuo, his assistant and a persimmon tree
(Version 5.5 of anti-goat enclosure in making.)

Nobuo, four assistants and a persimmon tree 
(Version 5.5 still in making.)

Anti-goat protective enclosure at work. Two days since it's launch and
persimmon trees are still surviving!

That was it about summer chicken jungle. More exciting stories coming soon... maybe, I hope.

Wednesday, May 17, 2017

How we killed 5 chickens and why

Belated news: About three weeks ago we killed five of our hens.

On our little farm this was the most massive killing so far, so it feels like I should mention it here.

It's not easy to write about killing our chickens. It wasn't easy to kill them in the first place. I don't want to be cynical (our chickens deserve better) or moralistic (our readers deserve better.) And I can't write poetry, so there's only one option left: a dry factual account.

So, we killed 5 hens.
This is one of them, just before having her throat cut.

One of our hens just before killing.
This was the first and the last time in her life
she was held by the wings like this.
(Getting ready for the throat-cutting position.)

Within minutes, the hen fainted and bled to death. Fast-forward twenty minutes, and this is what she (and her fellows) turned into:

How living creatures turn into food. Initiating and seeing that process first hand is so, so, so important.
Mysterious transformation.
When exactly does a living creature become food?

Hens were partly grilled, partly made into chicken soup.

Removing tendons from meat before grilling.

Chicken soup (Chicken bones are boiling inside. 
Floating on the top are onions, potatoes and a carrot.)

Meat had been soaked in sake (日本酒) for a few hours before grilling
Thanks to this magic trick it was tender enough and delicious. 
(Meat from a two-year-old chicken is usually too tough for grilling.)

How did we kill the chickens?

By cutting their carotid artery (major blood vessel in the neck).

Our instructor was Mr Hiroyuki Tanaka (田中啓之さん), farmer from a neighboring town of Ishioka who raises about 200 chickens,  sells eggs and sometimes organizes workshops where amateurs like me can learn how to kill, pluck, portion and cook a chicken (utilizing as much of it as possible.) We asked Tanaka-san to come to our place on this occasion.

Five chickens on the death row were separated from the flock the night before killing and their feed was withheld to clear their digestive track. It means they "fasted" for only about 12 hours and missed only one meal (breakfast). This, I believe, caused them almost no extra stress. (Some farmers recommend the no-feed period of 48 hours prior killing, others go for 24 hours. Cleaner intestines mean lower risk of 'spill-out' when butchering, but if you really care about chickens, the minimum of 12 hours should do.)

Why did we kill the chickens?

Born on April 28, 2015, our chickens are already two years old. Their biological lifetime is four or five times longer than that, but their lifetime as "agricultural animals" is normally less than two years.  In Europe, laying hens are usually slaughtered at about 17 months of age, in Japan similarly at 17-18 months or, if forced molting, which is still allowed in Japan, is applied, at around 23-24 months. (There are small differences between farms.)
Pretty short, huh.

If we go by the most common 17-18 month benchmark, chickens on our farm (now 24 months old) are already enjoying extra months of life (without ever experiencing forced molting).

Life of chickens on conventional versus our farm.

Click to enlarge

But by now, the flock as a whole lays fewer eggs, and some hens lay eggs of worse quality. The five hens killed this time were the ones laying less pretty eggs.

Two eggs laid on the same day by two different hens from the same flock.
The brownish egg on the left is okay. The whitish egg on the right 
is not okay (too fragile shell.)

This change in both egg quality and quantity is natural, it comes with age and nothing can be done about it. Of course all hens are as happy-go-fluffy as ever, regardless of their egg productivity. But the economic consequences for the farm are all too clear.

So we had to make a decision: Are we going to keep our chickens as "pets" (and not kill them); or are we going to stick to the original plan and treat them as "farm animals" (and kill them).

Needless to say, these categories are purely arbitrary - the chickens are the same in both cases. My ability to freely switch between "companion animal" and "farm animal" categories is a classic example of doublethink and the amazing human ability to hold two conflicting concepts in mind without feeling inconsistent and contradictory. Except, I do feel inconsistent and contradictory. But I still can beat that feeling with 'rational thinking.'
The 'rational thinking' in this case involved asking myself a question:

Would the chickens be better off if they were treated as "farm animals" from the beginning (so that I could be 'consistent')?

(My) answer: I don't think so. Our chickens definitely benefited from our inconsistent doublethink approach. They enjoyed the "companion animal" privileges all their life. Then they turned into "farm animals" on the very last day. In the ideal world, they could have stayed "companion animals" until they die naturally, but if that is not possible in the real world (not yet in 21st century), then the second best deal for them was the one they got.

Our chickens get Deal B.

By the way, there are over 130 million laying hens in Japan at this moment (Japan Poultry Association 日本養鶏協会 → click 成鶏羽数の推移). After spending their life in a cage, they are transported and killed en masse in a slaughter house. Maybe a farm like ours is an important alternative to those. So I decided that I'm not going to feel bad about killing our chickens. At least I will try.