Which is better, a pygmy goat or a nigerian dwarf goat?

I'm looking for a good milking goat, but i don't have much room, only a 8x10 ft. shed and a 10x5 ft. fenced in area which would be shared by 11 chickens. i also want a friendly goat, one that wouldn't mind A lot of kids. i was also wondering if my chickens could keep one goat happy instead of getting another goat.