I would love to be able to leave them out together, but will keep separate if need be. The few times they have come in contact the bantam Cochin roo attacked the standard. He will also jump at any standard hen that comes his way. They are both around 5-6 months. From what I have seen so far they have no interest in mating with each others ladies. The bantam pullets have wandered with the standard roo and hens/pullets without a problem or any interest in mating. They are caged where the others can see and have had some supervised contact. Spurs are almost nonexistent on each of them so if they go at each other I have no qualms about stepping in. They have twice and each time it was the Cochin that went after my golden comet roo and golden comet was just defending. Is it possible or am is it never going to happen? Is there anyone who has managed to do this?