Goats are browsers rather than grazers (sheep need grass), so freshly cut branches of things like willow, brambles, raspberries, hazel, some ash (can make them a bit runny), hung up in their run will keep them occupied and happy for a while. Thy will peel thee bark off, willow in particular. They also usually love rosebay willowherb
Cabbage leaves, carrot sticks, some apple slices, banana (incl the skin, but peeled off and fed separately) will also be good to give regularly.
I mean sugar beet shreds, as fed to horses. I always soak mine, just a dash of boiling water a few minutes before feeding time, and then add some rolled oats, topped with some of the veg mentioned above. A good source of fibre for cudding too.
I would be worried that these two may get too fat if they are kept as pets, so only a handful of goat mix maybe once a day - but in summer with grass, branches and veg at hand they would probably be ok without much added on.