[quote="Kris"]Any great stretches that barrel horses should be doing??[/quote]
Well Kris...here I could write a book...humm, not a bad idea....LOL !!
Before I start here...two things...always always stay within you particular horses range of motion..by this I mean, please dont pull his leg sideways eitherway....keep it within his normal "footpath"...some horses do "track" to the inside or outside a lttle bit...and you will know if your horse does when you pick up his leg.
Second....be gentle and hold the stretch for at least 20 seconds. Oh, and listen to what he has to "say".
Shoulder stretches....pick his foot up and move to the front of him...cradle his leg just under the knee (you want his foot to be a a ninety and for the lower part to "dangle"..great word..aye!) now gently pull forward you can see the muscles behind the shoulder stretch...hold for 20 to 30 seconds..then move your hands down the leg to the fetlock (dont go down to the foot here....this may harm the suspensorys) and continue to gently pull...this stetches the same area...but a different set of muscles...same deal..20 to 30 seconds.
Next we move the leg under the horse...like you were asking him to put his front foot on top of his back one. Important here to note that you put pressure just above the knee..support the fetlock but let it drop toward the ground...I could sure show you this way better...

This will stretch the front of the shoulder..you may even find your horse will drop his head and turn it away from you....gives him an even better stretch. You may notice that your horse is more free one way or it's easier for him or his stretch is bigger...can mean he needs some therapy..or he may be just need some more stretching.
Hindlegs....stretch the hamstring by picking up the foot like you were cleaning it..but pull it forward, through its range of motion under the body, hold for 20 to 30 seconds.....stretching the hip area...take the leg backward from there....I always cup my hands around the front of the fetlock and stay low to the ground...through the range of motiion and straight back. It is ideal if they totally straighten their leg here...cause this indicates that their stifles are in great shape...they can not straighten the leg totally unless the patella (kneecap) of the stifle joint is inline.
You can do a bunch of stuff with treats too to stretch their back and "open" the withers.
Also exercises over poles on the ground works well to get some movement in the hips and strengthen the gaskin muscles as well as everything around the hock.
There are definelty more stretches but this will get you started.