I have 8 Wellies in the incubator and they seem to be slow to hatch. One piped yesterday afternoon and has made very little progress. Another one piped at about 3:00am and neither are making any noise. They are due to hatch today. Is there is problem with them? Are they not strong enough to get out? I don't want them to die in the shells. They are the only chicks I will get out of my champion roo who was killed by a raccoon. Should I start to worry?