Awww, cute little ratties :lol:
Wouldnt worry too much about the wood shavings. If it is dust extracted, which most proper pet ones are now, it shouldnt cause a problem. Iv always kept mine on it...I have had a few!
I had babies a a year or so ago, so gorgeous when they are that age! Couldnt help but keep them, so I had 28 pet rats :lol: I only bred them as a one off to experience it, so they were all kept as pets after that which was great :lol: So friendly...:lol:
Hope you enjoy your little mates! :lol: