Over the last 3-4 years we have kidded 6-8 milkers each year. It's hard work!
We take the kids away virtually at birth, as we hand rear them right from the beginning. We actually take the kids indoors for the first 2 days or so, maybe more if it is very cold. They have as big a cardboard box as we can source in the kitchen/living room, and get to wander round the floor when they can manage the slippy laminate floor.
They then move back out to the goat shed, not into a huge pen, biggest pen normally would be about 6 by 6 when they are still wee. They get let out of the pen during daylight hours to play in the goatshed (or outside if it is ok weather).
Once they're about a month old is when we find they need the extra room. A stable would be great to keep in then. We had 7 kids this year in the 6 by 6 pen, but once then were a month they were split into two groups, both in 6 by 6 ft pen. Then the pen with 4 in got made bigger to 6 by 9 ft after another couple of weeks. They get a quarter size of a solid bit of pallet to jump on and play in the pen.
Really what you need the bigger pens for, is once they are a month, they are too jumpy and destructive to let run around the goatshed, and if weather is bad, they need enough room in the pen to get enough exercise.
I would utilise the stables for groups of kids- especially if you can open the door and let them run in and out.
Beth