But I'd never really looked into selenium before. I went out and purchased one of those salt licks with selenium mixed in. My mare happily licked it up for a little while - my pony just pawed at it until it was a big pile of dust and didn't eat any.
Then I looked it up. Apparently it's got a very small window of safety for horses between being deficient and being toxic. I suppose I should call my vet on this - but how do I know if my horses actually need this - being so dangerous I don't want to risk it. Aside from obviously a blood test. Is providing a selenium salt lick free choice a safe thing to do? Can it potentially cause toxicity? I'm beginning to wonder if I need to go take it out of their stalls now... Is it worth the risk?