I've had dogs and rabbits together and they all got on great, one little rabbit used to love cuddling up to my Tara, bless her. But, not all dogs are like this. It sounds like you're little dog is curious, so best to keep any rabbits away from him at first in their own pen until they all get to know one another. Rabbits are lovely and make smashing pets, so many of them are forgotten in hutches at the bottom of the garden, so good homes for rabbits are definitley needed!