Space will depend a little on your weather. I currently have 10 does sharing a 12x12 stall but they have 24/7 access to the barnyard and pasture (unless there's a blizzard). They can also go into two other 12x12 stalls but they hardly ever go in them. During the kidding season I've had as many as 25 goats sharing the one stall. During warmer weather they'll mostly go in at night or to eat but will spend the bulk of their day outside. In winter they'll mostly be inside but they seem to have plenty of room.
You can get goats that are already registered. You will get their certificate that's been signed over to you as the new owner. Then you will have to submit the proper paperwork to get them changed to be registered in your name. When I sell kids, I give the new owners the registration application. I fill out all the information for them expect the goat's name and owner info. I do it this way for 2 reasons. 1 - The new owner can pick a name they want. I have a couple I bought with names that would have never picked. 2 - If they don't want to register them, they don't have to. If they don't, I don't have a bunch of registered goats under my breeder info that aren't actually in my herd. The new owner is responsible for sending in the application.
Can't stress this enough. Test for worms regularly and only deworm when they have too many worms. And don't let them feed close to the ground.
