welcome here! i’m so glad you rescued a bunny! did they give you any diet info at the shelter? or what exactly did they tell you they fed her?
carrots and fruit are very high in sugar, so they should be limited to 3x a week. for a treat you can give a couple “matchstick” carrots (the slivers found in bagged salads), a thin sliver of fruit. or a grape or two. one of these, 3x a week, not daily… one baby carrot cut up would be enough for the entire week for a bunny. you can feed raisins as treats. since they are smaller, you can feed one or two of these per day. many of us actually cut a raisin into 2 or 3 pieces, so we can treat a few extra times during the day without increasing their sugar intake (think of it like, instead of eating a full-size snickers bar once, you eat 3 funsize bars at different times during the day). i keep a small container of their regular timothy pellets in the bunny room, and sometimes i will treat with just one of their normal food pellets. you can also use healthy herbs… treats can be anything that you feed from your hand to the bunny’s mouth.
the most important part of the diet is hay. she needs unlimited, fresh timothy hay or another grass hay. alfalfa is a legume hay and should not be fed to healthy, adult rabbits over the age of (approximately) 7-12 months. same thing with the pellets, they need to have a timothy hay base. on the back of the package, among the ingredients, timothy should be the first one listed. you want to use plain pellets with no added “junk” (no seeds, corn, cereal, or dried puffed pieces). these are not at all necessary as an additive of the diet. seeds and corn in fact can be dangerous to their health. cereal and other grains can cause diarrhea (aka poopy butt) as it throw off the gi tract and they can produce excess cecals. pellets should be limited to no more than 1/4 cup per 5 pounds of rabbit. feeding anymore than that can decrease their hay intake and that is not good.
after hay, the most important part of the diet is fresh, green leafy veggies. Bunny Love posted the page that details what can and cannot be fed. the minimum per day is two cups of veggies per rabbit. you can go up to 4 cups per bunny, as long as it’s not affecting the hay intake, but i’d start with the two cups… greens are very important because they keep the gut moving (along with the hay) and they hydrate everything. also, it’s most closely related to what a bunny would eat in the wild (grass and plants) and most of our buns love their veggies! you want to introduce them slowly. some good ones to start with are romaine and parsley. you will want to work your way up so you are feeding three different veggies per day.
this page talks more about diet… https://www.binkybunny.com/BUNNYINFO/Diet/tabid/60/Default.aspx
and this is a great article from rabbit expert, Dana Krempels about what to feed your bunny and why it is important… http://www.bio.miami.edu/hare/diet.html
if you have any more questions, please ask! we’re happy to help! 