I have a few outside piggies, and at night we shut them in the garage for warmth, but also so their safe from the foxies. We have chickens and had a bunny (who liked to beat up cats) and we've never had a problem in our area, but the people down the road with chickens set up a camera and there are foxes around. maybe check with chickeny people localy to see what trouble they're having? because if a fox can get into a chicken coup and massacre the residents, you might want to keep your piggies inside for peace (piece?!) of mind.
Put bolts on hutch doors, as those twizzly things will do nothing to stop a fox, and you may want to double up the wire for extra safety.
also, if you have a run seperate from the hutch, you may want to make sure thats equally safe, as my friend had a bunny taken by a fox, in -the day- when -they were there!-
also make sure they're nice and cosy at night, you can get hutch cosys these days, but take them off when it's warm, and in winter you might want to invest in some snugglesafe head pads (I/my girlies love them!) for warmness
love to your piggies!