Last Friday, 5/15, I hatched 4 eggs in the incubator, all 4 full siblings. By the fourth day I noticed one had started to develop wing feathers but then the growth stopped. By this Friday I could tell the chick's body was not growing either, and its wing feathers still didn't finish coming in like its siblings had. The funny thing is, this chick was vigorous, ate like a pig, drank very well, and had no pasty butt or odd poops. I found it dead under the heat plate this morning. I tried to do some online research, but all I came up with was malabsorption syndrome in boilers. These chicks are full Araucana. What could have caused this chick's stunted growth although it otherwise seemed healthy?