Take them off of the rabbit food! Rabbits are not rodents and have completely different dietary needs than rodents. Go to a feed store and get some lab block! Or some hog grower!
Rabbits eat mostly hay and grass, which is what their foo is made of.
Rodents eat mostly grains and seeds, which is what their food is made of.
Rabbit food is an awful substitute for rodent food, nowhere near complete nutrition.
If you want them to breed and be healthy and happy, you'll need to get them some real food.
Rabbit food high in fiber. Which not ok for rodents. At all. Calcium is also another high factor in rabbit food.