The only killing that I get is when I have a crowded tub with hoppers mixed in....I think the hoppers are just too lazy to reach for the water valves.
I'll see if I still have pics of the mice that had serious skin issues, within weeks of switching over to 19%. I sent pics to ADM, the only reply I got back was, they would look into it. I switched back to Mazuri after that.

Rich, are you using the Kent 23, or 16%? Just curious...
I just can't imagine that even your rats aren't showing signs of kidney problems on that high of a protein.... I've feed literally everthing over the years, and I have to say, by far, Kent 23% was the worst stuff I've ever tried. I had less deaths on cattle cubes with Urea, before I found out Urea was toxic to rodents... The only other time I've had so much trouble was on hog feed and the high protein there..