as opposed to what you find in a butcher's shop
http://www.iata.org/whatwedo/live_animals/

This is about, e.g., rodents which are fed to reptiles, right?

"Just wait until you get your first vet bill from feeding live rodents to your snake or lizard. Blood sucking parasites are out there, and are usually transmitted by feeding live. Ticks, mites, tape worm, round worm, pin worm, hook worm, to mention a few. For years now, I've been trying to educate herpers that freezing kills all parasites dead, reducing them to just a little more digestible protein.

Also, some rodent breeders aren't that bright. I've been told of one that brags to his customers that he doesn't have any problems with mites, because he just "dust the cages wood shaving with powder that kills them." I guess he's not concerned that the rats and mice would be ingesting this powder and absorbing it through their skin. Common sense is often uncommon.

If you have ever seen a snake or lizard with it's tongue bit out, or an eye bit out, you would never feed live. Unfortunately a lot of beginning herpetologists get into it for the wrong reasons. If they are honest with themselves, they just plain enjoy the "thrill of the kill." These are not our customers.

Also, most pet stores promote live sales, because while the mice and rats are in inventory, they just might grow a little bigger and get a better price, or better yet, they should drop another litter while they are waiting to be bought. Their best interest is not always your best interest."