Is he pooping?

If he’s eating hay, but dropping pellets and veg, it really sounds like a dental problem. Particularly since you say he doesn’t usually eat much hay, which is the main reason rabbits have dental problems. Rabbits teeth grow constantly, and hay is required to help wear them down. Eating other things just doesn’t have the same wearing affect on teeth.

I’m sorry, but a dental problem absolutely requires a vet. It’s not something that can be treated at home, and if it continues without treatment, it is likely that it will get worse, and could turn into GI stasis, which then also needs a vet. Perhaps you could talk to a vet about a payment plan? If you let us know where you’re based, we can also help with looking for a rabbit savvy vet.

I agree that this sounds like a dental issue. When rabbits drop food out of their mouths or only eat certain foods, it often means that they are having dental problems. As S & L said, dental problems will only get worse. If your rabbit has high spots or sharp edges on his back teeth, the teeth can start cutting into his cheeks and gums, which is very painful, and which would probably result in an abscess. This problem is something that only a vet can help with.

You may have to travel out of your city to find a rabbit savvy vet. Your rabbits are going to need vet care during their lives, so it would be good to know of a good vet to go to anyway. Since these were your sister’s rabbits, would she help you with the cost of their vet care?

Have you had your buns teeth drilled? I went to my vet recently and I learned (as a new bunny mom) that bunny’s need their teeth drilled every year or so due to their genetics. They go under anesthesia for it, and you have to syringe feed them for a few days. Unfortunately if the teeth are sharp, you can’t do anything to file them down but the drilling. My vet estimated it to be 250-300$ including the anesthesia, procedure, and ointments/powder food. I have a 2×4 ply of wood in my room that my bunny loves to chew on.

Kylo, I’m sorry but that’s just not true. SOME bunnies need annual or even more regular dental grindings, but it is certainly not something that all bunnies need as standard. Smooshed face bunnies (like netherland dwarves) are particularly prone to teeth issues. But, most healthy buns should be able to keep their own teeth growth in check with a correct diet, which is 90% hay. Hay is actually more important for grinding down teeth than chewing things like logs, as hay wears down the back teeth.
Of course, your bunny may well be one that needs regular dentals, but please make sure that your vet is rabbit savvy and isn’t just recommending it to all bunny owners as standard. And ensure that your bunny has a correct diet to make sure that the need is minimised as much as possible

The fact that he eats hay but drops other food suggests to me an incisor-issue. The incisors are the front teeth. Hay must be chewed with the inner teeth, and that’s what keeps the inner teeth in good shape.

Incisor problems are as a rule not as difficult to deal with as inner teeth problems. First of all you can see the incisors without special equipment (otoscope, sedation).

Some buns need their incisors pulled out, they will still be fine because the can pull food in with their tongue. Sometimes a bun has hurt one or two incisors so tgey need to be clipped by someone who knows how too.

Is it the bottom incisors that have turned brown?