Very interesting thread. I recently started breeding rats and my 1st male was a definite sneezer. The litter I just posted about is actually his and I'm really hoping that all of his babies aren't prone to being irritated. I will definitely be interested in selectively breeding his offspring to hopefully improve the over-all disposition of my breeding stock.

I also had a very bad experience this weekend with a new female that I picked up. She was making some odd noises that I just mistook for her being a "more vocal" rat. I believe she actually had some respiratory issues going on and died a couple of days after I got her. I'll post a separate topic about my experience to try and get some feedback.

I was happy to read this question. It's been helpful as I try to read up on the issue.