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Your Ultimate Guide to the ISA Brown Chicken Breed

An ISA brown chicken is an exceptional egg layer with a lovable personality to match. But don’t go buying your hens just yet. The breed’s greatest strength is the root cause of their weakness. 

And no, it is not just a simple lice infestation. It’s a matter of life and death! If you don’t act fast or keep up with their nutritional needs, you’ll end up saying goodbye to your very productive hen earlier than expected. 

Read our guide and prepare yourself for what it takes to raise these hybrid chickens.

ISA Brown Chicken breed In A Nutshell

Average lifespan3-5 years
Egg productionExcellent (280-320 eggs per year)
Egg color & sizeBrown, large to extra large size
Size / market weightMedium (Pullet: 3.5lbs; Cockerel: 4 lbs)
TemperamentFriendly to humans, docile, broody
Coop needsComfy nesting box with a spacious run
Cold hardy?Yes
Health problemsProne to prolapse and kidney-related problems
RarityParent stock is hard to come by

The Secret Origins of the ISA Brown

The ISA Brown is a hybrid chicken developed in France by the Institut de Sélection Animale. Hence, the acronym ISA. For over 40 years, these brown hens remained one of the top global egg layers (1).

That’s why many backyard chicken keepers have an ISA or two (and even more) in their flock. But not everyone can have pure parent stocks of ISA walking around their backyards. The ISA breeding formula is as guarded as the spice blend for the KFC Original Recipe chicken. But if people were to guess, a lot say they have some Rhode Island Red, White, and White Leghorns somewhere in their gene pool. 

The Red Sex-Link Chicken Appearance

ISA chickens aren’t unique when it comes to appearance. These hybrids actually look very much like the other brown chicken breeds. And a lot of people mistake them for Comets, Rhode Island Reds, and Red Star Chickens

The one thing you can get right with these birds is whether they’re hens or roosters. These hybrid chickens are also sex-linked. So as soon as they hatch, their fluff color tells you what sex they are.

It’s A Girl!

These fluff balls are light brown with white speckles. The white feathers become more noticeable when they get older, and their brown color becomes more of a deep red or chestnut color.

an ISA brown hen brooding in a red wooden nest box

They also grow to have white tail feathers.

It’s A Boy!

These chirping boys are the reverse color of their sisters. They’re white with brown speckles. But, no, that doesn’t make them ISA White chickens. Those are a completely different hybrid that lay white eggs. 

Just like other roosters, they get bigger and heavier than the hens. Their wattles and combs stand out more too. And the tail feathers are also white but bigger than the hens’. 

No matter the sex, these chickens have small, single combs and yellow feet. And they all have distinct white tail feathers.

What’s It Like To Own ISA Brown Chickens?

So, you want an egg-laying machine of a hybrid chicken? Get a glimpse into the life of an ISA brown chicken keeper. 

Cool, Calm, And Collected

ISA hens have a girl-next-door vibe. Everyone loves them and wants to be their friend.

They get along with their owners and other animals around them. But, they also like things the way they are.

These chickens need time to get to know newcomers, so introduce new chickens slowly. The good news is that ISA browns aren’t usually aggressive.

Well, at least the hens aren’t. Cockerels start to act out when they mature, kind of like a teenage boy. Just remind them who’s boss, and you’ll be fine. Overall, these brown beauties are a joy to have. They make good mothers to their chicks and great company for your kids. 

The Need For ISA Brown Eggs 

As we said, these ladies are one of the best egg-layers out there. They were designed for that purpose, after all. Imagine thousands of chickens laying over 300 large brown eggs per year. No wonder they supply about 60% of the commercial brown eggs in the market (2).

Their egg-laying ability is one of the main reasons people keep them around. But unless you want to supply eggs to your whole neighborhood, one or two ISA hens is more than enough to keep eggs on the breakfast table. 

Are ISA Chickens Good Eating?

An ISA bird doesn’t make the best roast chicken. If you have second to nothing left, by all means, dress one up and pop it in the oven. But these chickens aren’t sustainable meat birds. 

Why? It’s because they only won the egg-laying genetic lottery. You can’t have it all with these chickens.

Chatty Chicken?

Another reason to keep these chickens around is that you barely hear a peep from them. You can TOLERATE a chatty bird that gives you lots of eggs. But you will LOVE a chicken that is quiet about giving you lots of eggs. Your neighbors will also like them even more.

Caring For The ISA Brown Chicken Breed: What You Need To Know

You already know ISAs are the best-laying friendly hens out there. Check out what you need to do to keep them happy and healthy.

How To Keep Your ISA Brown Chickens Healthy

Egg laying is equivalent to giving birth. Now imagine doing it almost every day! Sadly, it’s this extraordinary ability that makes ISA Browns live shorter lives.  

Prolific egg layers are prone to prolapse (3). It’s when a part of the hen’s oviduct sticks out. It is dangerous because other hens can start to peck at it. If it goes out of hand, a prolapse hen can die. 

Good thing you can prevent this from happening. You’ll need to keep your ISA hens at a healthy weight. Be nice and don’t control their light exposure so that they lay more. 

Another common problem for these hens is kidney stones. Basically, their kidneys work overtime without getting or having too much of the right minerals. Not having enough water also adds to this problem.

On a brighter note, ISA browns are generally hardy birds that can adapt to different weather conditions. So as long as you don’t manage them in a poor laying setup, they should live up to 5 happy years.

Feeding Your ISA Brown Hens

Notice anything in common about the health concerns of these brown birds? Poor diet causes them. Yes, these birds don’t need to eat much to produce lots of eggs. But what little they do eat needs to be of good quality.

Give them lots of water. And feed them healthy chicken feed with a good balance of fiber, calcium, and phosphorus (4). 

“Supplementing poultry diets with “acidifiers” (ammonium chloride, ammonium sulphate) is useful to reduce the urine pH and prevent kidney stone formation.”

Feeding these hens the suitable feed is essential to keep them healthy and live longer. Remember that their unique abilities need special attention.

Where to House Your ISA Browns

ISA Brown Chickens take confinement well, but they stay happier in open spaces. Don’t worry about them wandering off too far. They like staying close to their chicken coop.

Keeping ISA Brown Chickens in a free-range system gives them access to tasty bugs. That’s free protein and good exercise for them.

A comfy, quiet nesting box is also a must for supreme egg layers. Make sure they have soft bedding and enough space. Consider a nesting box with an external hatch. It comes in handy when you collect eggs pretty much daily.

Where to Buy ISA Chickens

Remember when we said that the breeding formula for ISA parent stocks is a closely guarded secret? Well, that also means that you need to register with the ISA before you can get those stocks. 

If you don’t want to be bound by secrecy for the rest of your life, you can just get the commercial stocks. These chickens lay just as many eggs and are way easier to get. Local hatcheries usually have ISA brown chickens for sale, or you can always buy your chickens online

Here are some places you can check:

The Verdict

ISA Brown Chickens are great to have around. And not just because of the many eggs they lay. They’re borderline sweet and good-tempered enough for your kids to hang around with. 

If you keep them in good living conditions, these birds will stay with you longer than most other hybrids. So make sure you give them lots of water and good quality feed. Room to roam is always good too.


The difference between an ISA Brown and a Golden Comet is their parent stock. ISA Browns come from four secret chicken breeds. Some say that two of those are Rhode Island Reds and White Leghorns. 

Those two breeds are the exact parent stocks of Golden Comets. These chickens are also hybrids that lay a lot of eggs. But they don’t lay as much as ISA Browns. 

As for appearance, they look almost identical. These chickens are both brown with white specks. A noticeable difference would be in the eggs. ISA eggs are bigger than Golden comets, and they lay more eggs too.

No, ISA browns don’t breed true. Remember, these are hybrid chickens. A lot of science and genetic isolation happens in the breeding process. 

That said, you need the original parent stocks to come up with the commercial stock of ISA browns. Breeding these brown hens with other roosters dilutes the gene pool, and the offspring’s traits aren’t the same. Even breeding pure commercial lines together give off different results.

Yes, ISA Browns lay in winter. They are hardy birds that adapt well to different climates. They lay better under comfortable conditions. So, as long as they don’t feel too cold during the winter months, they should continue laying. 

There are a lot of ways you can make them feel safe and comfy. Setting up a chicken coop heater keeps them nice and toasty. Also, make sure they have a lot of water and continue giving them good quality feed. 

Keeping their nesting boxes clean also encourages them to lay more. You wouldn’t want to sit on cold soiled bedding, would you?

An ISA Brown hen lays eggs for about 82 weeks. They start laying at around 18 weeks, which is fast for the usual chicken. But it’s typical for hybrids. They were genetically bred this way to make the most of their productivity. Most heritage breeds start laying at 24-26 weeks. 

When these early layers start, they continue laying for over a year. They produce fewer eggs as they get older. And by the time they reach three years old, they stop laying eggs.

Yes, ISA brown eggs will hatch given the right conditions. The hens CAN go broody, but it’s not their usual instinct. They would make good mothers, given their gentle personalities.

But their default setting is to keep laying eggs. They can’t do that when they go broody, and that’s why it’s not normal for them to brood. If you want to hatch ISA eggs, you have to do it in an incubator. When they hatch, you have to take care of them just like other human-raised chicks.

  1. ISA Brown Chickens. Retrieved from:
  2. ISA Browns. Retrieved from:
  3. Management Guide Alternative production systems. Retrieved from:
  4. Kidney damage is emerging in laying hens. Retrieved from: