My horse has windpuffs, he came with them. They come and go. His legs tend to stock up if he misses a few days of turnout due to bad weather. But they go right down with walking and riding and turnout. 

Years ago I had a Morab that came to me with wind puffs.  He was out 24/7 with a run-in shelter so never stocked up.   Over time, he did develop pretty bad arthritis in those front legs and I had to put him down because of it when he was 27.

 The horse in my avatar stocked up when I first bought him as a 3 yo.  I had to board him until he was 11-1/2.  The first boarding place had cement stalls (old cow barn) and Duke was lucky to have 2 inches of saw dust in his stall.  If he didn't get turned out every day he stocked up.

The second boarding place also had cement stalls (also an old cow barn), but they bedded Duke with about 4 about inches of sawdust and Duke was turned out at least 12 hours/daily unless we had freezing/sleeting weather.  Duke never stocked up at that place and he has never stocked up since.

What he has in common with the Morab in my first paragraph is arthritis.  Fury's (the Morab) was in all four ankles and the fronts were really bad.  Duke's is hock and ankle arthritis, with one rear ankle being affected.  Duke will be 21 in a few months.

So while the stocking up and wind puffs aren't a big deal now, IMO, they are both possibly pre-cursors to arthritis. 

Your horse does deserve watching from that perspective and also consideration should be given as to the type of work you want him to do over the long term.  If you want an eventer for more than just fun for one or two seasons, my thought is to not use this horse for that type of long-term hard work.

Just my thoughts based on my two experiences  My horses have always been used for trail riding and some pretty rough riding from time-to-time.  I had to retire Fury from serious trail riding 4 or 5 years before I put him to sleep.

 Duke was 16 in my avatar.  That is a lunch break picture from what I consider a "not quite intermediate organized ride" in terms of being rough.  That was the last of those types of rides Duke went on.  He can flat-hack and climb a few small hills, but I make sure not to tax him too much.  He can tax himself in the pasture all the wants to, because he knows his limits, but I take it pretty easy on him these days ----------he's carried my butt for nearly 18 years and is well-deserving of not having to work too hard

A little while ago, I took care of a pony who was recovering from a tendon injury in her right hind leg.  She started to get windpuffs on that leg, so I polo wrapped her every time we rode.  This kept them from getting larger, and was recommended by our vet.  I have also heard that doing standing wraps when the horse is in their stall will help with stocking up.  Maybe you could try this and see if it helps.

 I too used standing wraps and saw them help. What really helped was enlarging the stall into a double size and letting her move around more. They're out 24/7 and no problems, but it too was happening on the odd nights that the weather put them in the barn. I'm a 6" deep bedder and I'm on dirt floors as well. 

I don't know if either of these scenarios is going to fit your boarding situation or not. Asking for more bedding, bandaging, or more turnout and walking and warming up plenty to get the flow going again before asking for performance would help.

The circulation is pooling and building from the bottom up, because its not getting away, because the horse is not moving and therefore pumping it up, so it pools and stagnates everything behind it. It's like he's dealt with the workload of the previous day, but can't make it gone and away for a fresh start. Now he's got leftovers to deal with, plus new  and even more homework to do the next day and no way to do it stuck in a stall. I can see a vicious circle inviting arthritis in the long run.I have been told that it's the pooling nasties that leave behind particles of aggravation in the joints that aggravate them and cause arthritis. Things must always flow...

 

stocking up is when the legs fill with fluid and just look big and puffy. Usually horses stock up behind up to the hock and in front up to the knees. Particularly in the tendon areas where you can really see little bones and stuff, that area is just filled and there is no shape to it. I call them fat legs =]

One of my horses gets stocked up in his hind ankles when he's not moving around.  With this weather - humidity and heat - they only get out about 5 or 6 hrs per day and he stocks up when he's in his stall.  However, I do have runs off my stalls, and they're usually not confined to only their stalls (except for extreme weather).  But when it's so hot and humid that we can't breathe out there, they don't even want to go out in the sun.  So it's his own laziness that gets him stocked up.  He used to be a pasture horse 24/7 and it's probably the best thing for any horse, but he can't tolerate the heat and becomes a non sweater, etc.  So, I have a stocked up horse when he's coming out of his stall.  It goes away after turnout or riding.