Breed Gentler Laying Hens

New line of birds promises lower mortality rate, higher egg production.


| July 3, 2009



A hen gathers her chicks.

A hen gathers her chicks.

iStockphoto.com/Sue Mack

A team of scientists led by Agricultural Research Service biologist Heng-wei Cheng at the agency’s Livestock Behavior Research Unit in West Lafayette, Indiana, and William M. Muir of Purdue University, also at West Lafayette, has developed a line of laying hens that display far less aggression than their commercial counterparts, while maintaining industry-standard egg production. As a result of this development, the researchers were able to cut mortality losses among the birds without the usual beak-trimming.

At 58 weeks of age, the selected line of hens had significantly lower annual mortality than another group of hens – called a “control group” – and a commercial line of laying hens. When housed in communal cages, the kinder, gentler line had a 20 percent mortality rate, compared to 54 percent for the control line and 89 percent for the commercial line. Egg production was increased in the gentler birds, compared to the control line and the commercial line under the same conditions.

Most breeding programs in the past 50 years have concentrated only on traits related to production. For instance, through more than 20 years of breeding selection, egg production has increased significantly in one commercial line of laying hens, while mortality due to aggression and cannibalism among the birds with untrimmed beaks has also increased about 10-fold.

Cheng and his colleagues selected breeding birds based not just on production traits, but also took into account competitive interactions among the birds in a group, or communal, setting. This selection program turns “survival of the fittest” – which emphasizes the individual – into “survival of the adequate,” which emphasizes the group.

Cheng is conducting further research to look at physiological alterations that explain the less aggressive behavior in the new line of hens. His preliminary work indicates this may be due to a decrease in dopamine levels in the birds. Dopamine is a neurotransmitter that has been associated with dysfunctional behavior, as well as with a decline in the ability to cope with stress.

ARS is the U.S. Department of Agriculture's chief scientific research agency.

patchlady
7/6/2009 1:18:08 PM

I remember a few years back, when I spoke for myself and expected fair treatment, being called some offensive names. Now, they want to label my hens "aggressive" if they would display survival instincts if "overstocked"? Let's call a spade a spade; it's not a "hen aggression" problem, it's a "human management" problem!


sparkyo_2
7/6/2009 8:56:04 AM

We have been raising chickens for years and have never had a problem with aggression or cannibalism. Currently, we have two batches of chicks and one batch is more skittish than the other. The second batch is as mellow as can be. It is our intent to join them together in the coop when they are ready, and we will continue to have mellow, laid back birds who are not confined to a cubicle the size of 2.5' x 2.5 x 2.5! Tell the researchers to go back to the drawing board and try their analysis with birds who are allowed to free range. Ours follow us around when we are out in the yard. They sure sound like agressive birds - Chicken Monsters!!!


janet
7/4/2009 4:46:14 PM

Has science considered observing chickens who are not confined in cages their entire lives, to see what chickens are really like? Packed into cages the size of Xerox boxes, never being allowed to follow their natural instincts to scratch and dust bathe, and breathing the ammonia fumes from all their waste piling up underneath them, I'm not surprised that chickens go mad and attack each other. Aside from their regular doses of antibiotics, I am suprised they are not given sedatives too!


sarahoz
7/4/2009 4:40:58 AM

this is an interesting development but it ignores the needs of a hen's system to have a rest from year round laying. a hen is not a machine for our use. sarahoz


geoffrey stover_2
7/3/2009 9:59:10 AM

You can't go wrong with Buff Orpington hens. They're docile, even friendly, dual purpose, a nice light brown and regularly produce large brown eggs.






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