Stray kittens

We have about 5 stray kittens outside. One of them is about 5 months or so not sure how months is it though. Anyway, my concern is that she is kind of moody. She used to be playful but since one of her playmate is not around she stopped playing. She eats and drinks. Most of the time she just sits in the homemade box we made. When she tries to meow there is no meow sound. Anyways, I took her to the vet yesterday and the vet says that she is losing her tooth and gaining it. She worries me though.

If you're not confident with your vet, look for another or ask for a second opinion.