ISA Brown Information Sheet

Author: Aussie Chook Supplies  

ISA Browns are an incredibly popular chicken choice, and that is mainly because they are the producers of the big brown eggs that you buy on supermarket shelves. Although they have an excellent reputation for egg laying, 95% will meet this reputation, 4% will be mediocre layers and 1% complete dud layers. We are referring to an animal with has natural variances, not a machine (which honestly, I think some people forget sometimes… LOL)

Please be aware that the name ISA Brown is actually a brand, much the same as Toyota or Samsung. The ‘ISA’ stands for “Institute de Selection Animale” – a French company that developed the breed in 1978 as a battery hen for optimum egg production. The ‘Brown’ refers to the chicken feather colour. There is also an ‘ISA White’ but this isn’t available in Australia. Baiada Poultry have the Australian rights to market the name ‘ISA Browns’.

Like everything that dominates the market, there are a other commercial hybrid chickens (such as Gingerham, Bonds Brown Hi-sex or Lohman) which are often indistinguishable in looks and egg production. Some sellers use the term ISA Brown quite loosely but upon further questioning will say that they ‘breed their own’ – please be aware that although they may be breeding a similar looking chicken that is robust, healthy and a great producer of eggs, they are not true ISA Browns. Either way you should be able to discuss the origins of your ISA Brown chickens from the person you are buying it from.

Genetic makeup and breeding of an ISA Brown

The ISA Brown is not recognised as a breed as it a hybrid, meaning that the girls (hens) hatch out a different colour to the boys (roosters) – ideal for the commercial egg industry. Also, if you mate the rooster to a hen you will not produce an ISA Brown chicken which is another component of producing a hybrid chicken.

The ISA Brown is not a recognised in poultry shows and cannot be judged as there is apparently no breed standard for them. Word on the street has it that the genetic make up of an ISA Brown is a closely guarded secret, much like the secret recipes of some well known restaurants so this is a topic of much speculation in the chicken world. This is also reflected by the fact that ISA Browns are referred to as ‘Products’ on their home website… 

Can I access/purchase the parent breeding stock of ISA Browns or ISA Whites?

Unfortunately this is impossible as the genetics are fiercely protected by the multi-billion dollar corporations that own them - like Baiada and Steggles. What you are asking for is the chicken equivalent of asking for the Coke Recipe cause you want to make your own Cola. The best you can get/do is cross an ISA Brown hen over virtually any rooster and then you'll essentially end up with a crossbreed with nowhere near the laying potential of the genuine product.


ISA Browns are a great starting point for people who are new to chickens for many as they are readily available from multiple chicken sellers and will give you a fantastic number of eggs. They can be quite affectionate towards humans, often happy to be patted or a cuddled – especially when they learn that you are the provider of food and treats! But this can be said for 99% of purebreed chickens also…

Personally, I am an avid supporter of keeping purebreed/heritage chickens for the following reasons (just quickly) – keeping the gene pool of purebreeds alive, the variety of chicken and egg colours are awesome and they are the original heritage breeds that were brought into Australia. Much the same reasons that some gardeners love heritage vegetables, so they can keep the original seed lines going… but I digress.

ISA Browns and other chickens

ISA Browns are quite ‘chookist’ in so far that once they are part of an established flock they can be quite brutal to newcomers. This can be overcome by ensuring that any new additions to a flock which has ISA Browns are of a similar size (if not bigger) and have plenty of room to run away until the new pecking order is established. We also recommend having more than one food and water station to decrease the chances of the newcomers being denied access to food and water by the more dominant ISA Brown.

It is possible to have bantam chickens kept with ISA Browns and is something that we do ourselves. Introducing the different sized chickens is actually best done when bringing your new flock home (or very close to if you have to get them from different buyers/locations). The logic here is that the girls will be having to adjust to a new environment anyway and even if you got them from the same buyer/location they won’t have lived together as a smaller flock and will still need to settle into their pecking order anyway… so the ‘normal’ amount of bullying and squabbling will take place despite any differences in size.

Egg numbers

ISA Browns (or it’s brand name competitors) are the producers of the big, brown eggs that you will find in most egg cartons. Egg for egg, ISA Browns are a great value chicken producing over 300+ eggs for an initial investment of $28 approx. per bird. This can only really be compared to other pure breed chickens or commercial layer strains of chickens which were used originally for egg production (i.e. The Australorp or Leghorn). They are also bred to begin laying at around 20-22 weeks of age, much younger than the 24 weeks plus of a pure breed chicken.

This image (below) is courtesy of Goode Paddock Eggs, who use ISA Browns on their free range egg farm. They are protected from predators by both an electric fence and Maremma Guardian Livestock dogs. ISA Browns in this environment look so much healthier and happier than cage farm chickens. As egg farming should it be. 

One downside to the fact that they will lay abundantly for the two years of their life is the fact that the ISA Brown can look quite “moth eaten” and will often have a loss of feathers around its neck and/or bottom. This is because they will direct the protein they gain from food into egg production instead of feather production, but a boost of protein and some Natural Chicken Health Health Plus Poultry Booster added to their food will help their feather regrowth and assist in continuing egg laying.


Although ISA Browns have a reputation of not becoming broody, it is necessary to remember that in a commercial caged egg environment there would be at least 6 chickens in a space 1m wide and 50cm deep with no actual nesting area (or access to natural light really).

In a backyard setting, ISA Browns are in a much better environment and do become broody (and are capable of being good mothers to chicks). Again, we are talking about a living animal with natural urges. We will not refund you for your ISA Brown purchase if your girl does become broody (and therefore stop laying eggs) although we will assist you to rehome them if you are really that unhappy with the situation.

Life expectancy

A common question from new chicken keepers are ‘How long does an ISA Brown live for?’ ISA Browns (and all commercial layers) have a significantly reduced life span/life expectancy compared to a healthy purebreed chicken – with a majority living for between 2-3 years. Some backyard chicken keepers report that their ISA Brown pets are living between 5-8 years but it should be noted, however, that this lifespan for an ISA Brown is in the vast minority as it simply isn’t what the chicken is ‘bred’ to do.

The decreased life expectancy is directly related to their high egg production – pure breed chickens will definitely moult, possibly go broody and a majority will take a break during the colder month to grow back their feathers (and rest their reproductive systems).

ISA Brown’s (and a lot of other commercial hybrid chickens) are bred to continue laying most of the year. This means that they won’t have the opportunity to rest their reproductive systems and will therefore develop tumours, cancers, prolapses and other health issues relating to their high egg production. Either that, or they will pass away from sheer  (egg laying) exhaustion. Very sad for the chickens and the owners who experience this loss.

‘Rescuing’ an ex-battery ISA Brown hen

Wanting to provide a home for a ‘rescued’ ISA Brown is very admirable and is very rewarding for the people who choose to do this. However this image is from Crystal’s Barnyard Pets in Melbourne and is one of many commercial egg farms that have utilised Crystal’s rehoming program. Note the absence of feathers, the lack of colour in their combs/wattles/faces and general unwell pall that these chickens have. Some chickens can have very short beaks, due to the lack of precision and care used when they were ‘debeaked’ as day old chicks…

Rescuing an ISA Brown chicken definitely involves a different level of care to those who are bringing home a ‘normal’ chicken. Aussie Chook Supplies advise that you research the issue and gain as much information as you can on how to care well for the rescued girls for the remainder of their natural lives (and realistic expectations of what kind of life they may have outside of a commercial environment). 

‘Cheap’ ISA Brown warning

A word of warning about buying ‘cheap’ ISA Brown’s which are readily advertised. Primarily, how old is the ISA Brown that you are buying… often the cheaper the bird the older it is. Young ISA Brown chickens (or any chicken really) will have a small comb (top red bit) and wattles (dangly red bits under the beak) which get larger and redder the closer they get to laying age. If you are offered a ‘young’ ISA Brown who has a large comb and wattle, please ask questions to satisfy any doubts you may have… Buying a $5 – $10 ISA Brown with the expectation of getting the 300+ egg referred to on this website (and many others) can be unrealistic if the seller isn’t being as honest as they can be.

However, there are also honest sellers who can provide an ISA Brown at this price because of either their location (in rural areas, for example) or because the girls are much younger and will not be producing eggs in the next couple of week. Point of lay as an general age reference, is around 24-26 weeks old – ISA Browns are bred to begin laying at around 22 weeks of age.

In summary

All in all, ISA Brown’s are a fantastic beginners chicken or for those who are wanting a lot of eggs for their time/money/food conversion. In our experience you fall into one of three groups:

1 – Perfectly happy with the fact they have a reduced life span provided that you get value for money from the eggs they will produce. We are talking about a chicken, right? This group will either turn their girls into a meal once their egg production reduces (or finds other homes for them) and come back to their buyer for another 4, 6 or 10…

2 – Buy them as a high egg production pet, looking after them and caring for them just as they would any other breed, grateful for the eggs while they get them and looking after their girls until they join the big chicken coop in the sky, whether they are laying every day or not at all…

3 – Me and/or the kids would be too devastated to loose a pet because of high volume egg laying reproductive issues. We would much rather have a purebreed that will give us less eggs per year (but more over their lifespan) and live longer…

So, which one are you? In answering this, you will also will determine if ISA Brown is the right type of chicken for you and your family…