Thanks, Matt and Linda for those links. After just briefly glancing at all of that, and remembering what I had come across for selenium toxicity (in swine and cattle, even from grazing cattle), it seems there is a safe range and feeding either above or below this range would be detrimental. I still haven't checked my premix label, but once having done that, it seems that you'd have to know the selenium content of your feed ingredients, too, to be sure you're not over supplementing or under supplementing. And of course, I haven't done a thorough read through these links yet, that info and much more may very likely be given. Cattle are our next project, so it seems to me that I need to be well-versed on the issue of selenium for the health of both species. For the time being, everyone looks good but of course these things have long-term effects we need to look out for.