I am having a problem with chicks that look fully developed and are dead before hatching. i keep my incubator at 99.5/100.9 and the humidity at 45/50. do i need to do something different? a couple of them couldn't hatch all the way out so i help and then they ended up dying. this pic is after they were in lock down for 2 days after they were supposed to hatch. one did have a little yoke in it, you can see it on the plate.