Can anyone offer advice on getting my Collie to stop attacking the chickens. We have about 24 chickens and started letting them roam the yard last week. They are about 2 1/2 months old. We have 2 seven year old collies, brother and sister. The female totally ignores the chickens and couldn't care less what they do, the male has attacked the chickens several times. We finally had to pen up the chickens but I really want to let them roam and free range the farm yard. How do I stop this normally docile dog from going after the chickens?? I will build a large pen if I have to but just wondered if anyone has had a similiar experience. Our collie is a great dog, friendly, good with kids and never before aggressive at all. He just has a thing about the chickens.