Would the bunnies dig dens or be satisfied with the shelters, do you think?
In my outdoor winter cages give them cardboard boxes stuffed with hay. They hay doesn't stay in there long, but when it's windy they do sit in the boxes - and chew them, so they have to be replaced often. The wood and wire cages have wooden houses which they also chew on, but last longer.
* chicken wire on the bottom of cages will not be strong enough, they can bite right through it.
* If you colony raise rabbits, the best method of making the pens dig-proof is to build a 'basement' about 4 feet deep and then fill it with dirt. The fence should be anchored into the foundation so rabbits can't dig their way out. Using this method you could manually cut grass and bring it to the pens. Ratio of bucks to does should be 1 to 4-6, and live traps can be used to catch the fryers once they emerge from the burrow nests at weaning.
* Regarding dogs & rabbits, the right breed will not see the rabbits as food. My heeler is very protective of the rabbits, even the newborn ones. He once alerted me when he found a kit that had been born outside the nest and fallen to the floor, and I was able to save it. A good dog will see anything that 'should' be there as something to protect and anything that shouldn't (ie cats) as a threat to be eliminated.