How old is Nutmeg now? Could it be that she's really neglicting this part when she's cleaning herself? I'm asking because this was exactly the same problem when Luna was a kitten. I got her at the age of 6 weeks, and she was simply too young to do a good cleaning job on herself. Especially her butt became very smelly with time, like you said, like dried urine and poop. On day I just put her into the sink and washed her butt. I think it was the uncomfortable feeling of wet fur in that area that gave her the idea to clean her rear end for the first time. However, from that day on, the stinky problem has disappeared.

Good luck with Nutmeg!

Kirsten