I had a dream

Sheep; oxygen; O3;
The sheep were being crowded into a dip tank. That's ok, it's part of sheep's life. The problem was, they were inhaling a form of oxygen they couldn't exhale. It would build up inside them then of course they would panic as they couldn't get rid of it. I was thinking O3, but it couldn't be that, because that's ozone. Then there was something about the Sheep Jesus, that I tried to explain or understand.