The females lose calcium when developing eggs but will regain it just fine while eating mice/rats. Feeding multiples isn't a problem by any means unless they eat more than they should. Most snakes won't do this anyways though I have one that will overeat so use common sense. If the snake is only 400 grams, don't give it 4 jumbo mice. While it's easier to feed rats, some naturally do better with mice. Since I have corns as well, feeding nights include a mix of rats and mice. My 'mousers' get offered rats and sometimes they take them, sometimes they don't. I always have someone willing to eat any leftovers. The one great thing about having more than 1 of these guys. No food is ever wasted.