Our mice get a variety of food, they get a hog grower ration (that is very comparable to the rodent block), rolled oats with molasses, bird seed (whichever variety is on sale when I mix the feed), high protein, small kibble dog food, any crackers/cereal/bread that the kids have given up on. I mixed this well and use it as their main diet, they get fresh veggies usually 1-2 times per week with their regular diet, they love veggies but won't touch fruit of any kind.
Hope this helps!