I am new to chickens, and we currently have 6 chicks. 2 of them have really crusty poop bums. Can I let this go? Will it come off on it's own? If I need to get it off how do I do it? I tried to hold them and pull it off of one of them but she seemed to squawk in pain so I stopped. I feel bad, like a bad neglectful chicken momma. Also, I want to get 6 more chicks. My brooder is plenty big enough, can I put the newbies in with my week old chicks?