He keeps picking at the feathers under his right wing and leg. He's just now getting his chest feathers and is about 3 or 4 weeks. I have 7 other chicks ranging from 1 week to 7 weeks in the same broader. One is a Brown leghorn pullet same age. None of the others are doing this. He is not peepijg in distress and is eating and drinking. Is the brooder too warm for him or is something else going on? Stress? Too crowded? Please help.