There is a book available for download called "Personal Milkers: A Primer to Nigerian Dwarf Goats" by Patricia G. Stewart that is really covers ND's and I would guess a lot would apply to Mini Nubians as well. Be aware that not all ND's are great milkers. Whatever you buy ask the breeder a lot of questions on how well the milking genetics are for their goats. In that book it says 2 ND's need 18 sq ft inside. That really depends on your climate and amount of outdoor space they have. Mine hardly go outside in the winter so they need adequate indoor space, and they're spoiled. I currently only have 2 does with about 150 sq ft in the shed! But I'm adding a lamancha soon, and when they have babies it gets crowded fast! You could build a shelter that houses both the chickens with separate access to each side, but separate them with wire fencing so the chickens can't get over to the goats and vice versa.