You do know, yes, that what he needs to learn is not to pick up his foot per se, but to shift his weight off it, and keep the weight shifted off? If you approach it that way, you will have a lot more luck. Arthritis, sore feet, or any other soreness (including back issues) will make a horse much more reluctant to hold his feet up, so that is something to consider. Also, when you say 'he would be lazy and try and lay down while you had his foot" I would point out that this sounds to me rather more like a horse that is either sore or has just never actually been taught TO balance on 3 legs, and is not being lazy so much as just being UNABLE. Worth considering. But definitely something you need to fix. Now, being mud season and not being able to do much else with the horses, would be a Real Good Time
Drain the land--put up fences and hopefully that will be it.
Yeah, people will put horses in all sorts of dumb places. When our house was built here, 35 years ago, it was by harness racing people who built a 1/2 mile track here too. Then, uh, springtime came. Half the track was underwater. They did not stay long. (Did I mention the barn floods too? The barn floods too.) The place has gone thru a series of other owners, although one stayed 15 years or so, but all have left in large part because, duh, it is a former swamp and in late winter and spring it floods.
(edited to add: we knew this before we bought it, though, as we saw it during springtime and plus it is really obvious from local topography that it's a low spot)
However here is a cheery note for you: I have HAND-dug some extra drainage ditches, more-intelligently placed, and we have taken some other smartish measures like removing a culvert that would always flood, ice solid, and then become a dam... and the place now floods SIGNIFICANTLY LESS than it did 5 years ago. We are still stuck with the barn in an inappropriate location, but by fixing eavestroughs, doing drainage ditches, and installing an extra sump, it no longer floods much at all. And we've reorganized the horse pastures a bit, dug a few ditches, and added as much gravel or road base as we can afford to the area near the runin shed each year, and the horses are now not in anywhere NEAR as much mud as they were before - I'd say they're better off than most horses actually. And that's without tiling, which we can't do as there IS no lower point on our property to run a drain TO (our surface water exits via a neighbor's field).
So cheer up, there is often quite a lot that can be done. Although you really may not want your horses at home
this spring.
One thing to watch is that with marginal land like yours, you need either to invest in a largish all-weather paddock, or (as a distant second choice) crossfence so that you can use the highest dryest paddock as a sacrifice lot in mud weather, and have as much other grazeable land fenced in as possible but take real good care of it so it doesn't get ripped up in the mud.
The other thing, since you are going to be re-fencing, is to spend the extra little bit of money to use EXTRA THICK fenceposts, have them driven (not put in dug holes) EXTRA DEEP, and if you use fence materials that will catch a lot of wind (like 4-board, or wire mesh -and really these are the best materials to use, probably) then plan extra "bends" in long fencelines. Like
______________
___________| not ___________________
The reason is that fenceposts in wet ground have a strong tendency to rot out quickly and get 'heeled over' by the force of the wind. Even if the fence was well constructed. THose extra 3 measures will really improve the longevity of your fence, honest... and as you know, fence is way too expensive to have to replace any sooner than necessary
Good luck and sympathies from another swamp
(although things have mostly flushed thru here now, and aside from the persistant lake in the front paddock that would take a heckuva lot of fill to ever fix, we're back to pretty good shape, and the ground is even a bit 'stiff' from frost right now yay), and happy ditchdigging,
Pat