He isn’t eating hay because his teeth are preventing him from eating properly. When the front teeth are overgrown like that it’s called “malocclusion” and is due to a misalignment in the teeth. There could also be some misalignment with his molars, so you should have a rabbit savvy vet do a full dental exam.
At this point you should get them trimmed ASAP, and make sure he’s getting enough to eat (even if it’s extra salad and his normal pellets) to make sure he doesn’t go into GI stasis. Trimming the front teeth is a pretty common procedure and is usually very easy for the vet to do.
Once you get them trimmed, he might start eating hay on his own. If not you can slowly reduce pellets to encourage hay eating.
.
.
.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.