they very well may be just resting
don't give up hope! wait that 48 hours and see.
if needed, here is a very thorough list of common hatching problems and causes:
http://edis.ifas.ufl.edu/aa204
you look for things like shrink wrapped chicks, whether or not they pipped through the air cell, how far along they got, if they were correctly positioned, etc etc etc. read through the list of problems, it'll give you ideas of what to look for. i've found that most problems have different causes listed, but usually there's more than one "symptom" you can glean from the eggtopsy, and then you can usually figure out what happened by looking for the common denominator in the causes.
if needed, here is a very thorough list of common hatching problems and causes:
http://edis.ifas.ufl.edu/aa204
you look for things like shrink wrapped chicks, whether or not they pipped through the air cell, how far along they got, if they were correctly positioned, etc etc etc. read through the list of problems, it'll give you ideas of what to look for. i've found that most problems have different causes listed, but usually there's more than one "symptom" you can glean from the eggtopsy, and then you can usually figure out what happened by looking for the common denominator in the causes.