I have 10 Black Cochin/Dominique or Dom cross chicks that are 7.5 weeks old and hatched and raised by a Mama hen. One of the cockerels (I think his mother was a Dom/RIR (she is known for being a bully) because he has redish feathers on his chest) was mercilessly beating up on one of his brothers. I put him (the aggressor) in time out for the rest of the afternoon by dropping a milk crate over him. He just wouldn't stop, even with me standing over them. I have no idea what to do about this. I would slaughter him, but he is still too small to eat (not even 8 weeks old). They range within the 5,000 sq ft poultry paddock I have my laying flock in, so crowding isn't the issue. The one getting picked on is such a meek little guy and really sweet. He calmed down nicely and let me handle him when he realized I was trying to help him The pictures are after I cleaned him up. You can just see how cocky this little monster (the aggressor) is in this picture.