I've been using pine shavings sold for horse bedding. I really had no clue that they weren't okay until a few days ago when I found this site. The pet store here uses them (no, we didn't get our buns from a pet store but the person we rescued from originally bought from a pet store)and all the store sell them marketed towards rabbits. I was really frustrated to find out that they aren't good for the bunnies.
You see, we've had two litters of kits (well, 3 but first litter was stillborn, all 10) and in our first litter of kits we lost one unexpectedly and seemingly unexplainably and another developed a huge abscess at 5 weeks old that continued to recur and cause issues until she was 7 months old and had to have a hard abscess mass removed along with a leg. We suspected pasteurella as being the cause of both the loss and the abscess/infection. Now I hear that pine shavings can cause respiratory issues and I feel horrible. We were truly doing what we thought was best for them.
Fortunately the second litter turned out fine and none of the others kits from the first litter ever showed signs of sickness (nor did the parents).
I went to the farm store today and found pellet bedding. It is also pine and I was concerned but bought it anyway because I felt like pellets would be better than shavings at least. I am happy to read that the pine pellets are okay. The pellet bedding is a new addition to our farm store. In fact, the two employees working today had no clue what I was talking about when I asked for a bag. They were outside on the sidewalk stacked on a big pallet right next to the pine shavings we always get. They kept asking if I meant the shavings. I explained a few times that there were pellets out there and one girl finally went out and brought a bag in. They were all like 'oh!' when they saw that I wasn't completely mistaken in what I was trying to buy. LOL
My daughter will like the pellets better too. The rabbits are her responsibility and the shavings make such a huge mess. We end up with shavings all over the house as she carries them in from the garage at one end to the bunny room at the other.