It sounds like you have yourself some rowdy little girls!
Most of the behaviour you describe sounds like pretty typical ratty habits. Particularly females, as they are much more lively and active than males. Females are great jumpers, greats runners, and great chewers (though this last trait is shared with boys).
I would say with Ruby and her jumping, she just needs more supervision, for you to make sure she has no where to jump to, and a little bit of training. Rats are very smart, and can be trained to understand limits much like dogs. My boys know when they are out on the bed, that they are not allowed on the side tables, where we keep the remote controls (a favorite item to piddle on!). Now, if I leave the bedroom, they will often quietly climb over....but if I so much as snap my fingers, they stop dead in their tracks! Sometimes it might take a quick clap of my hands, but they get the message, and understand what they are doing wrong. One thing I always do, is then reward them for doing the right thing. After I snap, when they come running, I tell them how good they are, and give them a treat...I really feel positive reinforcement helps a lot!
Rosy enjoying being under the sheet is very normal as well. My suggestion would be for you to turn lights down lower (or off), to encourage your girls to play out in the open above the covers. My Edgar has sensitive red eyes, and doesn't enjoy bright light, but once they are dimmed, he'll come outside the covers and cuddle under my chin
For chewing, my first suggestion is just tighter supervision, if possible. When they start chewing, tell them "No" and remove them from the situation. One of our older boys we lost this Fall, Templeton, loved to chew, and if he began chewing on my or Blake's jeans, or the couch, he was told "No" and placed back in his house. I would also often give him something hard, like a dog biscuit, or a hazelnut, to relieve his urge to chew. Eventually, he almost completely stopped chewing outside their house, and contented himself with what I supplied.
Perhaps try appealing to them with a Dentabone or nuts in their shells while they are in their cage, as it might help them stop chewing outside their cage.
I have never had to use it, but you might want to investigate natural chewing deterents, like Bitter Apple....but it's very important that it is a natural deterent, as your rats will ingest some when they try to chew. I don't suggest it, but if nothing else works you might want to investigate it further.
I hope this helps you with your rowdy rats, and I'm glad you enjoyed the page!
