I had to laugh at Frank's comment a bit. Years ago I was buying frozen rodents from a herp society up north. I was thawing some out and one sort of came apart a bit. I noticed it had a stomach staple in it. I was a bit puzzled for obvious reasons and of course concerned as well about feeding such rodents to my reptiles.
Given the location of the herp society I guess they were getting them from a nearby major university with a medical school (herp society meetings were held on campus during the winter). After wondering what in the hell else they may have been subjecting these rodents to I started raising my own.