I don't know if I have something similar going on here with Willow. Today as I let her out I noticed that she was making weird noises. I have never heard anything like that: it's a kind of a murmur, a bit like water simmering under a lid, occasionally lifting it, or some low-pitched creaking wheel. She does not do it all the time - I listened to her for about 20 minutes and it's not continuous (so it doesn't sound like she is wheezing or there is something wrong with her breathing). Apart from the strange noises, she looks completely normal, eats like a horse, poos look normal, runs around in her usual lively manner. And no, she's not spayed either. She was doing it while happily eating a cabbage leaf, so it didn't give me the impression that she was distressed.