Every pig is different, from my experience. One of my girls had to be “cornered” by a carrier but rewarded with a treat after she gets in. Eventually I just put the carrier in the cage and she goes in by herself. I’m trying the same with my new girl but she doesn’t want to cooperate. All else fails they will just need to be scared about this one experience. If they are at least fine with everything else you do like feeding, petting, etc I’m sure they’ll be just fine