I am new to having chicks and chickens.WE got the fever and dove right in. We we purchased about 20 baby chicks at about 3 days old. We had 2 die but all the other have been healthy and are about 4 weeks old. They are still in the brooder but we do take them outside during the day time. We purchase 3 more chicks the other day 2 are 6 weeks and 1 is 8 weeks. 2 brahma and 1 copper maran. The maran strated looking weak yesterday and today it is now not moving and wing feathers hanging down. It also has a bulge on its chest. I am worried this could effect all my flock. What is it? And what do I do about it. It seemed fine when we got it.