My oldest chick is about 3 weeks and I'm not sure if it's a growth spurt or something else. Do chicks normally go through a growth spurt where they put on weight? He seems kinda heavy compaired to his 2 week old companion. Is it possible to overfeed chicks or do they just eat until they get full? Maybe I'm just overly concerned about Biddy's weight and roundness. He does seem to be growing quite a bit though.