Some of my newly hatched baby chicks have swollen necks a few hours after they have hatched. They are not surviving. I haven't ever had a problem like this when incubating eggs. Only two of my chicks have survived so far and they are perfectly fine, but the last three that have hatched had trouble getting out of the shell and then they seemed really weak and ended up with swelled necks and died. Any suggestions on what might this be and just wondering if it had to do with the incubation period. Thanks.