Behavioral issues at daycare

So I have an almost 4 year old in daycare. He’s very recently been lashing out and hurting the other kids. I have no idea why as he doesn’t hurt me and we live with my mom and he doesn’t hurt her either. I’m having to pick him up and leave work several times now. He is in a classroom with kids who are 2 and my son is very tall for his age nearly 44 inches so he’s already bigger than majority of these kids. I don’t know if it’s a staffing issue at the daycare but i’m sure this isn’t helping. But what can I do to stop this ?? I’ve stopped spoiling him because i’m not rewarding this behavior.