Back legs off at a canter?

Hi Everyone!
So my TBxWarmblood gelding has been a great boy up until about four days ago. Last Friday we were working in a large field when I noticed that at a canter he seemed to be stumbling a lot, especially when we turn at all. Big circles, small circles, just turning the corner of the field, etc. I thought it might just be an off day and let him hang in the stall overnight. I came back on Saturday and he was doing it even worse. It was almost like he was losing balance in his hind end. I got off and checked saddle, tack, and feet for stones. I lunged him to see what was happening...and he is doing this weird thing with his back legs almost like a bunny hop! Like instead of one hind leg hitting and then another, both are hitting and pushing off at the same time.
Anyone ever seen their horse do this? Know what causes it? It has never been a problem before.

Also, any thoughts on if equine chiropractors are a quack or a good idea?

Thanks!

Just under saddle? What about lunging? Is he ataxic at all?

you'll get lots of opinions on here as far as chiropractors go. I think they are a good tool but all lameness issues need veterinary attention first and foremost. This, however sounds more like a balance issue.

Can you have someone watch you while you canter it sounds like he's cross cantering? Feels like you're riding a washing machine. My boy likes to cross canter on his left lead due to a fibrotic myopathy in his right hind (he has been vet checked many times and is sound to ride). My friend's horse also does this when she is out of balance because her mare is green and needs lots of help balancing. If it is a cross canter issue, there are several other threads on here that I found helpful! Good luck.

I had a thoroughbred famous for his four beated canter. If its just at the canter in might not be lameness. Is his head bobbing at all?

Thanks!
He is doing under saddle, lunging, and when out running with the boys in the field.
What is ataxic?

Ataxic is trouble moving, basically.

I would have him vetted. He could have pulled tendon/muscle....could have a stone briuse.....could be graveled (gravel moving up the white line causing abcess).....or any of a bunch of problems. If it came up overnight, as it sounds, it is more likely an injury than a strictly balance issue.

Any puffiness or warmth along the hoof or legs? Head bobbing? Tenderness to pressure on his sole?

Ataxia is a lack of balance, not just trouble moving.

What you are describing, Wren, could be a gait issue associated with pain but with it getting worse I would be very worried that it is neurological in nature. I would strongly recommend that you have a vet out as an emergency visit to see your horse.

If this is neurological, then it could quickly progress to a situation where your horse is dangerous to himself and those around him due to an inability to control his own movements and balance enough to stay upright. Until your vet arrives, I would recommend that you move your horse into an area where there are no sharp protruding objects, he has enough room to get up if he falls and where he can't get his legs caught up under need a fence rail, etc if he does fall. Also advise that no one handles your horse until after a vet exam--both for his safety and theirs.

If at all possible, you should take your horse's temperature to see if there is any fever associated with these symptoms. And think about things that have occured in the days prior to the onset of symptoms. Has he been hauled? Had any sort of accident? Has he had or been around any horses with an upper respiratory infection in the last couple of weeks or been around any new horses?

Well the vet has been called, and I am now anxiously awaiting a reply.

He hasn't fallen over that I know of, been around new horses, or trailered recently. He doesn't seem wobbly. I looked up wobbles and did a couple of little diagnostic tests (spinning in tight circles, crossing legs, etc) and he did everything the same as the healthy horse we also tried.
Boo. I'm just worried that it is going to turn out to be something horrible.

Think about it this way: If it is something horrible at least you will be finding out what it is and treating it sooner than later.

Hopefully the vet will find out it is nothing and you will be relieved.

Without seeing it, it sounds like a locked stifle. We have a TB who occasionally locks up and does the same thing for a few strides, and then he's back to normal. Hopefully your vet will find something definitive. Good luck.