I recently started 70 chicks, 50 esas that I bought and 20 that I hatched. Everything was fine when suddenly I found a dead chick. The next day two. Then I noticed that several didn't look well. the next day six dead and they all looked sick. I kept the water fresh and the feed, but they didn't seem to be interested in either. The dead piled up and all I could find online was that chicks are expendable. Finally, the dying slowed two, one then none. The remaining chicks are rising hell again, eating well and chasing one another. I have about 40 left and am in a quandary. What happened???? Anybody have any idea.