I have 7 chicks of various breeds and unknown sexes in a bin together. They are about 5-6 weeks old. Normally they are very happy together. I have one silkie and one mutt(?) who flap their wings and 'chest-butt' each other. What the heck is THAT all about? Does this mean they are roo's ? Noone else plays that way... They have lots of space, they are in a 45gal. bin right now with perches, etc. No pecking, just the chest-butting. I am baffled.