Cockerel's glamour secrets revealed

Experts analysed the behaviour of cockerels and hens

Cockerels produce more sperm when mating with "sexy" chickens with big crests than with old hens they have bred with before, a Leeds expert has discovered.

Research found that male fowl use sophisticated tactics when mating to boost their chances of fertilising eggs.

The cockerels give less sperm to hens that were past partners and more to glamorous hens with "large sexual ornaments" according to research published in Nature magazine.

The "ornaments" include the combs or crests on the chickens' heads.

Promiscuous hens

University of Leeds animal scientist Dr Tommaso Pizzari says that, in human terms, the cockerels found these combs sexy.

"They seem to base their copulation decisions on the expressions of these female ornaments," he said.

The research, which was conducted at the Swedish University of Agricultural Sciences, found cockerels behaved like this because the hens were so promiscuous.

Dr Pizzari said hens mated with several different partners during their reproductive cycle so sperm from different cockerels must race each other to fertilise eggs.

"It is a bit like a lottery really, the more tickets they buy, the more likely they are to win the fertilisation game," he said.

The cockerels seemed to become bored of their partners after an initial bout of frequent mating.