Vit. E & Selenium + hay question

Just curious if the other maritime provinces have this problem ?

Our soil lacks Vitamin E and selenium, therefore our hay as well. There are a good few horses that have been diagnosed with deficiencies in the province, let alone the ones that don't get regular vet care. (there's another rant on it's own.. :/ ) One of the mares at our barn is on 2000 Units of Vitamin E, her selenium levels were fine.

Our hay guy get's his hay tested to see the quality, and has up'd the protein levels in the last year. What is a healthy protein level for hay ? Is it different for square vs. round? we feed mainly round bales, but feed square in winter at night when they are inside.

I recently switched to HiFat HiFibre, as it has higher percent of Vitamin E & Selenium then what I had him on before (purina checkers / haystretch) which he is doing fine with right now -- but I know they had him on it before I got him in the past and he got HOT. He is doing fine now where it is summer and in regular work, so he is burning off any access energy. Our barn isn't blessed with an indoor so our horses get the winters off, which concerns me that he may become hot over the off season.
What other options could I put him on without making him hot? I want him to have healthy levels in his diet, and prevent him from getting deficient in Vitamin E and Selenium without the excess energy. I know it's more common for Quarter horses and Draft's to become deficient in it so I've become a little paranoid ha ha.

Thanks for the help :)

I started buying Legacy supplement from Co-op. It apparently doesn't keep well, they bring it in special order, so I'm hoping the half bag I have left keeps good for the summer. Purina Equalizer made Arrow hot-hot-hot- buggy eyed after 3 days on it...