Two days ago, I noticed that my 4 week old barred rock (don't know if it is a roo or not) had a bulging behind. It was just hanging out like a bubble. My husband and I put some TUcks on it and today it has gone down quite a bit. He is eating, drinking and behaving normally other than he "struts" and "crows" which the other two are still just making "peeping" sounds. Does anyone know what the bulging business is all about. We have searched all over the internet and cant' seem to pin down what is causing it.