June 12, 2009

 

A team of scientists from the Agricultural Research Service (ARS) has developed a line of laying hens that display far less aggression than their commercial counterparts, while maintaining industry-standard egg production.

 

This development was able to help reduce mortality losses among the birds without beak-trimming.

 

At 58 weeks of age, the selected line of hens had significantly lower annual mortality than the control group and a commercial line of layers.

 

When housed in communal cages, the less aggressive line had a 20 percent mortality rate, compared to 54 percent for the control line and 89 percent for the commercial line.

 

The selected line also had increased egg production, compared to the control line and commercial line under the same conditions.

 

Researcher Heng-wei Cheng is conducting further research to look at physiological alterations that explain the less aggressive behaviour 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 behaviour, as well as with a decline in the ability to cope with stress.