Rabbits don't actually need many pellets. An adult rabbit, probably about 2 tablespoons a day. A young rabbit will need a bit more than that because they need the energy to grow. 95% of their diet should be good quality hay A bowl full of pellets is too much I would say.
I wouldn't bother bedding them on straw, I'd just give them hay as bedding; it's warm and it's very nutritious.