Richard its not just hear say.
Chickens are like Cows, not wishing to be rude at all "They go all Lesbo if there is not any "Cock or Bull around"? thats true. Ask your Vet.

When I was at reform school we were taken to a Educational Farm in East Sussex and while we stood among the cows one mounted another 'have you ever seen a cow on two legs there enormous well the cow underneath run off and the cow on top came crashing down and nearly pole axed my friend Spencer. He had to be carried from the field and taken to
East Grinsted Hospital he survived the episode with a bout of delayed concussion.