I have been raising chickens forever and have never had a problem with chicks. Last Tuesday, I purchased five chicks from our local feed store: two Wyandottes, one Americauna, one Rhode Island, and one Barred Rock. They all looked healthy. I put them in a cardboard box with plenty of food and water and put them on our radiant heated floor on top of a mat. I have done this with every batch of chicks I have ever raised. When I checked on the chicks Wednesday, one of the wyandottes wasn't looking very well. I took her out and put her in a smaller box under a heat lamp, but she died later that afternoon. Thursday, the other wyandotte was on her side and died later that afternoon. This morning, the Americauna was dead. I have never raised either of these types of chicks before, so I think I screwed up, but I don't know what I did wrong. Any help would be appreciated. I have six more chicks coming from a breeder in a month, and I don't want to lose any more chicks. The Rhode Island and Barred Rock are doing great.