mice have 12 teats, and while they will grow more slowly, they will probably be kept fed in stages. Sometimes they will separate them into different piles and feed them that way, or they may get help from other females if they are available.
It wouldn't hurt to cull some of them if possible, or foster some with a female in another colony
This is another reason why ASF rats make good feeders, the females have 20-24 teats. It's quite a sight to see one female feeding over 20 fuzzies at once. Looks like crowd surfing.