Ours are all outdoor piggies. During the winter/autumn they sleep in our shed at night, they are very snug in there and away from drafts. They get put out in their runs on nice days for exercise and grass, then get brought in at night. This is what we're doing at the moment.
During the spring/summer they are outside in their runs on the grass full time. We cover the indoor bit of the runs with tarpauline, so they keep dry and they have their igloos in their runs too, so got a couple of places to go in and out of. It's very windy where we are, but the pigs get used to it and it really doesn't bother them.
We've just got a couple of new babies (we'll have had them a week tomorrow) who have slotted into our regime perfectly. They are so happy to go outside. They have Amber to help keep them warm at night as well, but to be honest the shed stays very warm, so even in the snow all the pigs were very snug.
I'd do something like this with yours: wait for a nice day then pop them outside for a few hours. Bring them in at night. Do this until it remains warm at night, so summer time. Your pigs will not have grown a winter coat, so you must be careful to ensure they don't get cold. It's too cold at the moment to leave them out all night, but we may be able to start putting ours out in March if the weather continues to improve. The difference with yours is they are indoor pigs, so the transition needs to be even more gradual.
