I bought some chicks from the local TSC and 3 have died already and another one isn't looking so well. I have had them for about a week. They act fine and then all of a sudden they act like they can't breathe well and then they die. I have no clue what could be wrong with them unless it is something they could have caught in the brooder at the TSC. I have other chicks that I hatched myself and they are doing fine it is just those from TSC. I don't know what to do, please help!