For our girls pen (we have 3 ND does), we have 4 foot noclimb/woven wire fence, with 1x6 headers at the top, making it just under 5 foot high. It is set on posts 6-8 feet apart.
For their pasture (which is almost done!), we have posts spaced 7-8 feet apart, 4 foot high welded wire fence (5 foot in one low area on a hill) with 1x4 headers over the top, making it about 4.5-5 feet tall. Inside of that by about a foot, we are putting in electric tape at just-above ground, nose, and just-above head height, to keep them from putting pressure on the fence at all. Any gates are lined with woven or welded wire.