Can rabbits eat store-bought mushrooms

No, rabbits can't eat mushrooms. Some mushrooms are actually poisonous to rabbits, but even mushrooms that aren't poisonous are not healthy.

Rabbits should eat a diet of lots and lots of hay, some high-quality pellets daily, and some fresh greens daily. Some fruits and vegetables are also good as a treat food. See the related question below for more details and links.