Lots of frozen rodents get squished & fragile parts (tails, feet) can break off when frozen just because they're brittle (in the past, some have wondered if that's a quality
issue as well), but to really tell, you need to take one out of the bag & sniff, or thaw & let the snake "tell" you. Snakes couldn't care less about appearance, but normally
will refuse if spoiled. (although some king snakes etc. aren't so picky & feeders should not be fed if spoiled, that's why I sniff first... )
Rudeness is the weak man's imitation of strength. Eric Hoffer(1902 - 1983)