My local feed store had quite a few birds returned because many of the chicks were popping up with problems in their development. The owner sent the feed they were on and 6 chicks to UC Davis to be tested. The chicks arrived alive and were killed to be necropsied so the tests were run on both the live birds and dead birds. The birds came from McMurray and I was certain that the problem initiated there. However, the findings concluded that the birds were fed a feed insufficient in vitamin B-3 and calcium. The feed is "Poultry Extreme" and comes in a predominantly black bag. We were using the starter/crumble. Fortunately, I had been giving my birds vitamins in their water. I think this helped. The owner of the feed store called the feed company and they are working with the feed owner. The store owner has been using this feed exclusively for years and hasn't had any problems. It just seems that there was a bad batch.