[hillfooter]

This problems occurs rarely about 1 in 100 however it is more common with Marans, it can happen to all breeds of chicken............

1 in a 100   I must have been unlucky and they weren't even Marans, Welsummer, Barnevelder, Vorwerks, Modern Game, Orloffs. Leghorns I've had aggressive cockerels from all these breeds and 50% + is the sort of ratio I've found.  If anything cockerels brought up with other cockerels have been less aggressive.

HF