Yes, you can mix two hays and average the ESC+starch numbers as long as it's done at each meal. You can't feed one hay at one time and the other one at another time. The other thing you need to do is make sure the horse is actually eating both hays, not picking thru and only eating the (usually) higher sugar one. The only way to actually reduce the sugar (not starch, as it won't lower with soaking) is to soak.
Iron at 267ppm is higher than needed but is a number that can be balanced to. Part of the higher iron may be on the surface of the hay, which can be lowered by shaking out the hay before feeding it. To know how much that may help, you'd need to test some of it after shaking. Surface iron will also rinse off (not soak) but that means you will need to rinse all of it before feeding then retest after the rinsing to see what the new result would be.
Although it's a pain, hay can be soaked in freezing temperatures if needed - many of us have done it at one time or another. Horses generally don't mind haysicles.
Lavinia, George Too, Calvin (PPID) and Dinky (PPID/IR)
Nappi, George and Dante Over the Bridge
Jan 05, RI