They should be fed daily. They should ideally be fed a number of different things per day, not just one thing.
I feed Zoomed pellets [soaked in water so they're soft], spring mix [w/o spinach; I pick thru to make sure I get a variety of greens], kale, collard greens, radicchio, mustard greens, chard, dandelion greens, to name a few. Google to get a list of safe plants and weeds (make sure pesticide-free!) and just offer the pellets plus at least 4 diffr greens per meal.
Morla (adult Russian tort) eats about 3-4 pellets plus about 7-8 spring mix leaves, and about 1 leaf (ripped into more manageable pieces) of whatever 3 other veggies I give her that day.