A dog biscuit once in awhile is going to hurt nothing, he isn't producing milk

so the animal fat in it isn't a biggy really. Your goal with your guy will be to read everything you can on urinary calculi, trying to keep his diet as ungrained as you can, high in calcium never phos....and if you have to feed grain, because some folks think they do have to or you are starving their goats, than feed a meat goat pellet that contains ammonium chloride so he doesn't produce urinary calculi, or buy some ammonium chlorid, it's super cheap and add it to his grian everyday. In reality unless you guy expends a great deal of energy hauling wood with you, or going on long hikes frequently his diet doesn't need to be much more than a really good mineral, really clean water, good hay....if all you get is non discript grass hay and alfalfa pellets added would be great.
Welcome to our forum! Vicki