That's fine when they will take pre-killled(most don't) and when your collection is only a few snakes but when you feed 50-100 snakes what Robin posted is what most breeders do with out incident.
I feed over 100 snakes a week, 97% live and have never had a problem because I feed appropriate sized rodents. Most folks run into problems because they are feeding too large of a rodent that is also dehydrated and starving. This is a formula for problems.
The only snakes I pre-kill for are my kings and boas.