I think the problem may have been a day that the temp jumped to 102 in my circulated air bator. The eggs came from 2 different sources, 3 different hens as they were all different breeds. One hatched on day 20 and the other 2 on day 21. The humidity did fall to 24% one day when it snowed, but was consistent besides that. It seems one had a birth defect and couldn't stand at all. It could only hop like a frog and kept getting the feet up over the wings. My husband culled it for me. One of the other 2 has completely recovered after not being able to stand at all with the help of the band aid therapy. The other walks around fine and only gets spraddled again occasionally, but it refused to keep the bandaid on for long.