Skip to Content

ISA Brown Chicken Breed: A Wonder Hen Developed in France

The ISA Brown was, for many years, the commercial battery hen of choice for the production of brown eggs. Today, it has fallen slightly out of favor but is still a popular choice. Due to the friendly, calm nature of the ISA Brown and their ability to adapt to a range of living conditions, they also make excellent chickens for families.

Key Takeaway

  • High egg production
  • Adaptable
  • Friendly and calm
  • Heat and cold tolerant
  • Great for kids and beginners

Background and History of the ISA Brown Breed

The ISA Brown chicken isn’t a true breed but rather a brand. They are an F1 Hybrid sex link chicken. Meaning they are the first generation offspring of two different types of chicken, and the chicks can be sexed on hatching by coloration and markings.

Origins of the ISA Brown start from hens that were first imported to France from the USA in 1959. These birds were commonly known as “Warren” hens after their breeder Jim Warren. Although capable of producing a large number of eggs, the eggs themselves were disappointing due to their brown shells and less-than-impressive size. In America at that time, extra-large white-shelled eggs were all the rage. 

Annick Studler, originally from Costa Rica, moved to France and started a career as a chicken farmer at the age of 22. She purchased some Warren hens and brought them to France. Without her, these chickens would almost certainly have disappeared entirely.

It was in 1976 that the Warren, after being developed by the Institut de Sélection Animale (ISA), became known as the ISA Brown with Annick Studler’s help. 

The company continued to develop the bird through a series of scientific breeding initiatives, and the parent company behind these changed through a series of mergers, including Babcock in 1981, Shaver in 1988, Hubbard Group (a Merck & Co subsidiary) in 1997, which renamed the hens Hubbard ISA. 

By 2001 forty-two million of the forty-five million laying hens in France were ISA Browns. 

Hubbard had two strains of hen, a layer and a broiler, and these two sectors were split in 2003, the layers branch was named the ISA Group, and by 2005, Merck had sold all of its sectors subsidiaries. 

The ISA Group sold to Natexis, and then a merger was made with Hendrix Genetics.

By 2017 the popularity of the ISA Brown in France was superseded by the Lohmann Brown. A genetically selected F1 Hybrid was developed in Germany by the company Lohmann Tierzucht. This hen is almost identical in appearance to the ISA Brown, but its egg-laying ability has been further enhanced. It is also a more popular choice as a free-range hen. 

As for the breeds which make up the ISA Brown, this is a trade secret, closely guarded by their creators. It is speculated that the breed contains Rhode Island Red and White as well as White Leghorns, but it is likely that other breeds are also involved. 

Because the birds are hybrids that don’t breed true, there is no standard of perfection, and they are not recognized by breed societies or the American Poultry Association. They are, in effect, copyrighted, and you cannot call a bird you have produced yourself an ISA brown, even if they look identical. 

It is still possible to show ISA Brown chickens at poultry shows, but they would not have a purebred class.

This type of chicken is not endangered. 

ISA Brown Temperament and Behavior

ISA Browns are known to be very affectionate, sweet-natured birds with docile personalities. 

They enjoy receiving treats from their owners and can often be held on your lap and cuddled, making them great for kids.

They also make a good choice for a backyard hen for both beginners and seasoned keepers, as they are also relatively quiet and adapt well to both confined living or being free range.

The only real downside to the ISA Brown is that they are relatively short-lived, with a life expectancy of between two and eight years, often depending on how well they are cared for. 

Some also think they are rather ordinary looking. Still, they are an excellent addition to a more ornamental flock, being passive and good-tempered while providing an abundance of eggs.

If you are looking for a heat-tolerant hen, they stand hot climates well if provided with deep shade and a constant supply of fresh, clean water. They are also good in colder areas, provided that they are given a warm house to retreat to so their combs don’t become frozen. 

Breed Specifics and Traits of the ISA Brown Chicken Breed

The color of the ISA Brown hen can vary slightly from pale chestnut to a richer shade of red. They will almost always have paler feathers, particularly on their tail, which can sometimes be almost white.

Roosters are predominantly white, and this makes them easy to sort the males from the females on hatching as the boys are pale yellow and the girls are a tan color.

They are medium-sized with a high tail carriage and rectangular body shape. The comb is red and single, and the wattles and face are also red. Their eyes can be a range of colors from red bay to yellow.

Hens weigh approximately 5lbs while roosters are closer to 6lbs.

Because hybrids don’t breed true, any chicks produced won’t be the same as their parents and probably won’t be as productive.

Although it’s unusual for a hen to go broody, as this trait has been bred out of them, sometimes they do. When this happens, they sit well and make excellent mothers.

Health and Disease

Unfortunately, ISA Brown chicks are prone to kidney problems, and adult birds rarely live a very long life as they were engineered to produce high numbers of eggs. This results in them burning out quickly unless they are very well-fed and kept in a healthy environment. They are also prone to tumors, many have reproductive problems, and prolapses are common. 

Because they are considered commercial birds, they would usually be killed after two years of production. It is normal for the number of eggs they will lay after this to reduce and makes the balance between feed costs and output unviable for farmers.

In some places, these commercial, often “battery” hens are now being sold on to chicken enthusiasts. Usually, they arrive with their new owners, thin and devoid of most of their feathers. However, with a little TLC, good food, space, and the provision of fresh water on tap, they soon recover and make wonderful pets, with the bonus that they still lay a good number of eggs. 

ISA Brown Eggs

ISA Browns can lay 300 to 320 large, brown eggs a year in their first couple of years, which really makes them egg-laying machines. They are one of the best productive breeds, but the price is paid with their short lifespan.

To help them stay healthy and lay for longer, a good diet is essential. They require a quality, high-protein feed that contains all the vitamins and minerals for egg production. 

Crushed oyster shells are also vitally important to help keep their calcium levels high; this helps them to produce strong egg shells and keeps their bones and feathers healthy. 

Getting Your Own ISA Brown Hens 

If you find a commercial egg production farmer, it may be possible to take chickens from them, often for free, after their first two years. 

It’s best not to buy chicks of this type due to health problems. Point-of-lay hens are a far better choice and can be found at some hatcheries or specialist breeders.

Should you wish to try raising chicks yourself, they can be purchased from Hoovers Hatchery, among others. 

Prices for chicks are per chick, and the more chicks you buy, the less you pay for each. You will have to order a minimum quantity as stipulated by the hatchery.

  • Male = $2.28 to $2.92
  • Female = $3.82 to $4.44
  • Unsexed = $3.03 to $3.65

These prices are a guide only, as the hatchery may change them at any time. 


If you’re looking for a prolific egg layer with a fantastic personality that is easy to care for and gets on well with other chicken breeds, then the ISA Brown would be a good match. 

Their main problem is their short lifespan and potential health issues, but with good care and feeding, this may be overcome to some extent. 

Getting your ISA Browns from a commercial enterprise is a great way to obtain some for little or no cost and to save the hens from slaughter. 

Ex-battery hens are some of the most affectionate and show their appreciation for a wonderful new life to their owners.

Questions and Answers

Here are some of the most frequently asked questions and their answers.

Q: Are ISA Brown chickens friendly?

A: Yes, ISA Browns are usually very friendly and docile chickens. They seem to enjoy human company and are docile among other breeds of hen. This means they are great for new chicken keepers and children. 

Q: How long do ISA Brown chickens lay for?

A: Although they are most productive in their first two years, they will continue laying throughout their lives, although you can expect the number of eggs to diminish as they age

Q: How many eggs does an ISA Brown chicken lay?

A: These amazing chickens will lay almost one egg a day and range from around 300 to 350 during their most productive time. 

Q: At what age does ISA Brown start laying eggs?

A: The ISA Brown pullet reaches the point of lay from around 22 weeks of age. This is variable and may stretch to 26 weeks and very occasionally longer. 

This site uses Akismet to reduce spam. Learn how your comment data is processed.

This site uses Akismet to reduce spam. Learn how your comment data is processed.