We have had 5 previously healthy chicks die in the last 2 weeks. They had been eating, drinking, acting normally, but one by one over the last 2 weeks, we would wake up and find one dead in the box. The one that just died this morning, I noticed blood on his butt, and it appears that another one has the same problem. Any idea what this would be??? These guys are 2 + weeks old, and are eating chick start, and drinking fine right up to the point where we find one dead in the morning. This is our second batch of chicks this summer, and we had no trouble at all with the first batch. The only difference, is these particular chicks are from another source than the first batch.