Rabbits tend to be a little reclusive and can be remote, but their strong desire for sweet stuff will bring them up to nuzzling your ankles or standing up on their hind feet with their legs on your knees!!!
I'd guess raisins are fine, but I'd think they are too sweet.
My opinion as to the best rabbit sweet. A one inch slice of banana. The banana skin should show traces of green....they don't like too ripe bananas. Why develop a banana habit with your rabbit?? Because when it comes time to give medication to your rabbit, you can cut a conical depression in the top of the slice and easily add in 1 1/2 ml of medicine. Bunny medicine is flavored sweet. When you give bunny its banana slice, it will painlessly lick out the medicine...We did this for years with Bunny.
Adding bunny medicine to a banana slice to be licked out is sooooo much easier than grabbing the rabbit and forcing a syringe in it's mouth and forcing it to drink....grabbing the rabbit creates a struggle, etc. The banana slice technique is soooo much easier.
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Our rabbits love apple slices, guava slices. I'm sure in season bing cherries will be a big hit. Actually they like apples so much, they will jump on the coffee table and dining room table when we are asleep looking for apples.