Fasting in adult females is nothing to worry about, and the weight loss isn't significant. They might be in breeding mode, but I wouldn't recommend breeding them this season, as they are probably still stressed from the move, and if there is an underlying health issue, going through the breeding and egg-laying process would be just about the worst thing you could do.

For now, I would just wait. Leave them alone and keep offering food every few weeks. If they continue to lose much more weight, you might consider taking in fecal samples (if you can get them) for testing.