I give mine fresh veggies in the morning and in the evening and none of them have the runs. 2 are young ones one of them 7 weeks. I did start the smallest one slowley in a different cage, still twice a day but only a little bit each time.
As soon as mine hear the clink of their veggie bowls they wheek like mad, they love it.
I would try some every day and then give a bit more as they get bigger.
I give a few types of veg as they don't like everything, one likes one thing while another likes something different. Spring greens are a BIG favourite here along with coriander and basil.