Two chicks have died. One that died its belly was purple and had no hair there. The brooder is very sanitary. I have six chicks and two ducks. Im more worried now that four other chicks are starting to get bald spots on their bellies and one has a greenish tint. Another has a dark hard spot there almost like a scab these chicks are 1-2 weeks old. If any one thinks they know what is please help. Also is it contagious?