My boyfriend bought me an incubator, so I jumped in and put 8 of my eggs in it. Wound up with 6 chicks from Red sex link hens, and a Speckled Sussex rooster. Needless to say these 4 week old babies are very colorful, but still beautiful. I've noticed recently several of them seem to have 1 breast a lot larger than the other side. Its quite a difference. Should I be concerned?