Make sure that you are maintaining high humidity so that they are able to move around their shells. I had this happen to me on my last hatch. I had set six eggs and four managed without any assistance but two struggled. After discussing the situation with an experienced hatcher I finally stepped in and gave a helping hand. One survived. It turns out the humidity was not sufficient enough and that their feathers started to dry and stick to shell membrane. With that said, the little peeps would rather die then ripe their feathers off. At the same time, they must do the majority of the work themselves and actually lift the head up for being folder under their wing of they will have not will to live later on. That is what happened to me. I started by assisting with cracking and removing the top part of the shell (with the shell sitting upright in a egg carton for support) and allowing the chick to lift it's own head out and emerge for the shell. One did this and the other did not. After about 12 hours I fully assisted the remaining chick from the shell. Unfortunately, it die three days later and never had the will to live. So that's my 2 cents.....hope everything works out.