As stated moving can be very stressful. That certainly can be one cause. I can't speak to your corn I really know very little about them. I have two ideas about you royals that might or might not be it over the moving stress.
If I remember correctly from other posts you have made you balls are close to adults now (at least the males)? Wild Royals lay within a short period of time all of them there IS an enviromental trigger the problem is it is to the best of my reading no one has diffinatly settled what it is. It could be a temperature thing or a pressure thing hard to say but it is possiable that the move has altered the right or combination of elements to trigger a breeding season and cause a fast. Just a thought.
The second is you mentions no weight gain or low weight gain. I have had to deal with this lately so it is in my mind don't freekout is is a long shot. I have a Royal that has always been fed frozen/thawed her whole life, I know the breeder well and in this case he is 100% sure that she has only had frozen. She is a great feeder but has been small tiny really as she was a twin and has other issues this wasn't a massive alarm bell. She stopped pooping and then started to be a sluggish feeder so off to the vet she went. The end result is she had tapeworms. Apparently it takes at the very least 48 hours and safer 72 hours at -7ºC (19ºF) to kill all traces of tape worms eggs. I had my freezer at -5ºC and at least once got fresh frozen (less than 8 hours dead) rats and feed then the next day. This also could be a cause, fecal exams are not super costly about 40$ it might be worth it if everything else checks out.