My pigs are outside now but they were never proper indoor pigs over winter. They live in our conservatory which is warmer than outside but not as warm as indoors.
The issue you have now is the days are lovely yes, but the nights are not. It's quite chilly tonight, I was out sweeping up with a jacket on. For this reason pigs who have lived indoors all the time may not adjust so well.
If you want to move them out, I would get everything ready then wait for a really warm, sunny day with cloud forecast overnight (keeps it warmer). Pop them out ASAP in the morning so they have a nice warm day to get used to the air, wind, etc. At night, cover them up and if it is chilly put some heatpads in and make sure they have LOADS of hay and puffy bedding - shredded paper is very good for this and very insulating.
If I were you I would still give it a few weeks though, especially if the bedroom is hot. Do you have a shed they could go in to help adjust?
Also please remember some of the hutches with runs attached (i.e. a ramp you just lock up at night) are quite nice for Mr Fox...I have never trusted them myself and like something properly solid I can lock up like Fort Knox!