I've found that when they've killed and taken the heads (the brain being the highest protein) the tank was crowded (which doesn't make sense to me, as there were only 10 babies) and/or the adults needed more protein. Giving them a little kitten food along w/their "Becky's mix" kibble and the rodent blocks seems to have helped.

Maybe their getting too old??? I lost 6/10 getting brained, and another litter was born right after that happened, but it's only five babies.

I'm not an ASF guru by any means, but maybe those brainstorming ideas will help you. Good luck!