Hi mwellmaker,
Was there anything that happened yesterday to egg on this kind of behaviour? Did your dogs not get as much excercise as they usually do? Pent up energy can come out of dogs as bad behaviour, so I'd try to make sure they have opportunity to get it out of themselves during the day!
Sometimes dogs, especially young ones, just get in the mood to destroy something or play with something they normally wouldn't. It just like human children who decide something glass looks good to push around, and break it. My own dog gets in moods sometimes to destroy drink bottles and the underdoor draft protector in the front hall...these are not good play things! You might just have a case of the two pups getting excited and grabbing the first thing near them.
To try and prevent it happening again, be sure to watch what your dogs go for during the day when you're around, and be quick to verbally correct them when they choose inappropriate toys. Its all about setting boundaries, and doing it repeatedly!
I understand wanting the dogs inside at night for protection, but to avoid this kind of thing happening you might consider dog gates or shutting doors to block access to rooms overnight. You can keep them so they can roam the hall and your bedroom, but nowhere else. I think this might be the best bet, since as you said, you don't know what they get up to when you're asleep!
Hopefully this helps, and even more hopefully it was just a random play thing they got into.