I'm agreeing with everyone, and only adding that separating is a good idea. Some gilts/sows can nick the other sows babies and so one ends up with all of them and the other has none, and it isnt great for all parties concerned. If the weather is warm I'd get them out as soon as you can, say day 2 or 3. If you can and your stables are warmer than their arks, you can always let them come and go for a week or two before out into the field, though thats only if we are having an unusually cold summer, I'd probably only do that in winter/late autumn/early spring.