do u know how low and long has humidity dropped? i've read that not enough humidity may cause shrink wrapping.
if u can bring up humidity to 65-70 ASAP, by putting wet paper towels inside.
also give the pipped eggs at least 24 hours to zip.
my quail eggs started hatching on the 16th day, last saturday. last chick came out yesterday afternoon. whenever i retrieve a fluffed chick to move to the brooder, there's a drop in the humidity but not for long. i also misted with warm water.
i am using a DIY styrofoam incubator and and my eggs were shipped. i'd say i did not have the best situation, i have 9 hatched out 59. still early to say that hatching is over, as i can see pipped eggs.