green leaves sometimes are rich of calcium and low in phosphorus and this is not a good balance if the piggies eat only that. You can use the online calculator by Guinea Lynx website, it is practical, easy to use and you can be sure of the balance of your diet. Anyway my piggies have been eating green leaves every day since their birth... or green fresh grass... the grass they are eating now is rich of calcium, too, but its ratio calcium/phophorus is balanced and their wee looks clear as almost never does when they eat only vegs. I suggest you to feed your piggies with the common green grass, also dandelion leaves which is a diuretic and helps in washing the bladder. Keep an eye on the quality and colour of your pig's wee, if you see some powder similar to talcum you should adjust the diet. Moreover, vit C decreases after some hours from the harvest, therefore fresh grass picked up from the lawn and .immediately offered to the pigs is very rich of vit C.
Also bell peppers are rich of vit C.
(anyway I use also a little bit of supplement in drops, the one for newborns)