I think I'm losing one of my chicks. Went out to the brooder and she is near lifeless, laying on the floor. Other chicks walking over her. My husband is going out to humanely finish her, as we hate to see her suffer. I have 12 total and my chicks are a mix of 2 weeks old, and less than one week old. The one that's dying now is under one week. They're on unmedicated food. I've noticed some runny poop in the brooder - dark brownish and some that's more black. Could it be coccidiosis? Should I get med from local Tractor supply? What kind. I'd hate to lose any more and want to do what I can to help them. Any help is appreciated!