You shouldn't ever have to feed ten mice. Four or five maybe, at the most. Adults don't need 10% of their body weight every week. If I ate as much today as I did when I was 18 or 20, I would be the size of a house!

The biggest issue with feeding lots of little bites instead of one big one is just that it's inconvenient. You feed one, wait for it to go down, hand over another, wait for it to go down, hand over another, wait around, hand over another.... It's much quicker to feed one prey and be done.