Originally Posted by LittlePanda0
Does rabbits have food allergies? You know like dogs to chocolate. Plus is it okay to feed your rabbit more fruits than vegetables besides hay?
It has nothing to do with allergies, it's simply toxic. Some things are toxic to some mammals, but not to others (like choclate (toxic to most mammals, I think only a few primates tolerate it), grapes, and imho onion for dogs, but not for humans)
Being herbivores, rabbits can stomach quite some stuff, wild and free ranging rabbits also use some (somewhat) toxic plants to medicate themself. There aren't that many things that can knock a rabbit out of it's boots (that story about appleseeds is blown out of proportion, nonsens), but they may need to learn how to deal with stuff, putting a house bunny into a patch of lillies of the valley might end badly.
About diet, this is how I see it:
Their digestion system evolved for fresh grass, weeds, leafs, some twigs and bark.
Hay is an acceptable, convenient substitute for that, along with some veggies and good pellets the rabbit gets everything it needs.
Since their digestion is adapted to a rather lean diet they can develope problems when there is too much sugar (fruits, some pet shop food and treats) or starch (grains, too much of some veggies) in it, like wrong gut bacteria or yeasts. Not to mention that extra calories nobunny needs, being fat is something pretty bad for a rabbit.
I feed forage whenever possible, but I reckon that isn't an option for everyone, and it is a lot of work. But when they have more than enough grass and weeds mine even ignore apples. In winter, when feeding hay, they don't bother if they take one of my fingers along with their daily slice of apple, topinampur, beet, or whatever available, but that's harmless compered to giving them some green grass in winter.
Anyway, whenever you change something in their diet - do it slowly, in the course of about a week, they need the grow the right bacteria to adjust to the new situation. There are some quite safe plants, like plaintain (grass weed), leafs of roses, raspberry, blackberry, apple leaves...., which don't need that much time and come in handy in an emergency (rabbit not eating).
I try to keep their diet as diverse as possible, many different things, everything in moderation - that imho makes problems due to changing diet more unlikely, and lots of the healthy stuff (grass, weeds, hay)