Hundreds of cockerels have been abandoned by people who tried to raise hens amid fears of an egg shortage during the first coronavirus lockdown.
The novice owners bought fertilised eggs and then hatched them themselves in the hope of having hens which could lay edible eggs.
But when in many cases male birds were born instead, owners decided their noisy crowing was too much for them and their neighbours to bear.
That, coupled with new bird flu regulations imposed in December, meant that the RSPCA was forced to deal more than 1,500 cockerels and hens in 2021.
Other unscrupulous owners have taken to dumping them in the countryside.