I'll just respond to you both at once
@liza and
@aiminglow, since your questions are pretty similar.
The bridge is actually a grate type of bridge. So you can see through it down to the bottom. There is no water there yet since it's still too cold for the lakes, rivers, or creeks to thaw out. So it's just snow. It's honestly mostly just a really deep and steep ditch (though looks flat and even with all the snow in it right now). I literally have to take about 3 steps to get over the bridge so it's very short.
This kind of bridge messes with most horses because you can see through it. So it's kind of like an obtical illussion for them due to how they see things differently than us. So while we can understand that there's a grate there and it's safe to cross and we won't fall through, horses see it as there's something there, but they can also see the ground under so they become very unsure if they can actually step there and cross or not.
Although, sometimes the water around a bridge makes it scary as well. I had a mare last year that was only scared to cross a bridge if there was water under it. If it was just over a dry ditch or something, she didn't care. So sometimes certain horses are just being weird with why they refuse at bridges.
Also, no, refusal at that bridge isn't new. I've never ridden him over it before, but the last time I led him over it, there was a very minor reaction to it. But he seems to lack confidence when he carries a rider since he spooks more when being ridden versus led, so that's something I'm definitely working on figuring out how to solve.
This is roughly what the grate part of the bridge looks like except also a deep green color (so it blends in more with the grass during spring and summer). Also the one on the trail is at least twice as wide as this one with different railings. But this is to give you an idea of what him and I are up against with his spooking.