I have 10 8-9 week chicks. I believe 3 of them are Leghorns (hatched from TJ fertile eggs) 2 of those are roos. The other 7 are EE and I am not sure which ones are Roos. my coop is small (still brood size) but there is a door for them to go out in the run. My run is about 13 feet wide and about 30 feet long. here's my issue. I am noticing at least 4 of the chicks are belly bumping each other and playing "who is taller" they do pick on the other chicks as well. Especially the leghorns roos. is this normal behavior for such young chicks? I am new to chickens and I am a first timer.