No, it isn't medicated. The protein is 20%, but they are only fed that twice a day. The rest is free choice on greens, mostly what they collect while in their tractor. Their growth rate seems good. They eat all the feed I give them pretty quickly with only a little left when they lose interest and start to graze.
I have one theory, though.
While I was gone this weekend, my husband said they got loose in the garage. I'm wondering if they got into something. Like the self-clumping kitty litter. How much would it take to kill them, and how long would it take to do so? They seriously looked totally normal an hour before I found them dead, and this was three days after they would have gotten into something, assuming they did. But it is all I can think of.
And no, they've never been without water, except over night. I'll watch that. I don't think they were overly enthusiastic about their water this morning when I gave them their dish, but that will be good for me to watch for.