Hi 

He is over a 1000 lbs weighs 1,130.Can hear rattling, wheezing when i put my ear near his nose...

Was humid and hot for about a week, also had horses in for training that got sick with strangles,they are now gone home. He's not showing signs of sickness no fever no thick yellow snot. He's not been getting 2 oz of salt a day won't eat out of feed,most he'll eat out of feed is an 1oz a day. I'll syringe the other 1oz into him then. Maybe he's coming down with strangles?? other horses though didn't have labored breathing so not sure strangles is his problem?? 

He does have thick whitish snot that drains out of his nose every so often when he puts his head down.Still labored breathing this morning and coughing,will give him a dose of albuterol here see if that helps him.

I'v maximized environment control no straw no hay stored in horse barn,all feed is soaked, stall bedded in wood shavings. I try and keep him outside as much as possible,right now though horse flies are bad so he's in 12 hours a day.