I wouldn’t even say the horse spooked “badly.” Just hit the wire somehow, and then spooked.
It could have been anything.
With the feed bucket hanging right below the hot wire, it would be so simple to happen to anyone, even an experience person. The horse could have simply misjudged the distance when he picked his head up.
I ASSumed only the OP was allowed to use it that way, if we use it back we’re “mean girls”

IF THEY DID, we observers would notice and stop them.
How?
The average horse weighs 1,000 pounds and can run 44 miles per hour.
Are you guys also on horses so that you can chase them down? Are you skilled ropers?
Or are you armed with tranquilizer guns?
About a year and a half ago I was bringing in the sweetest little 19-year-old QH mare at the farm where I used to board. She was fairly new to the barn, and she’d come into heat and was being a little wiley, but she always minded her manners with people. I’ve started babies from day one, raised, started, trained horses, restarted horses off the track, handled mares and stallions in the breeding shed. You name it, I’ve done it. 35 years of experience with these critters.
I had a momentary lapse of judgment and when I put the mare in her stall (with feed and hay in), I somehow left her stall door ajar just enough and she whipped around and was past me and heading right back out before I could get my head on straight to realize I’d messed up. I tried to stop her, but she was on a mission.
Knowing I needed to keep her on the property, I ran and shut all of the exterior gates so that she was at least confined to the yard area around the barn. I opened a gate to an empty pasture, hoping she’d run in there. There were three other horses on the place: my gelding (in his own pasture, unconcerned about the loose raging hussy); another gelding that she’d been out with (somewhat excited about the loose raging hussy), and another mare (in her own stall/paddock situation, VERY excited about the loose, raging hussy). This mare strolled around at full speed, tail flagged, snorting, screaming, bucking. I tried to catch her and literally fell down in the process of trying to zig when she zagged. She would have run me over, no doubt. I finally brought the two geldings into their stalls and the loose mare went to the other mare’s stall where they stood squealing and peeing at each other (lovely) until I was able to sidle up with some feed and catch the loose mare.
When she wasn’t in heat, this mare’s owner routinely free-grazed her while grooming etc. and she was gentle as a lamb and quiet as a mouse. Seriously, she is a lovely little horse.
Never. Say. Never. And don’t count on being able to “stop” any equine once it realizes it’s free and is determined to go on a tour of the farm, neighborhood, etc.

If your horse is blanketed/ unblanketed every day, there isn’t really much you can do that will spook them during the blanketing process unless they are a nervous/ spooky individual but you say your horse isn’t that type.
Every once in awhile reading this thread I recall that someone shared that the OP’s nickname for her own horse is ‘Sir Spooksalot’.
But, yeah, definitely blame the young person on duty that evening and definitely bother her parents about it while they are dealing with a difficult family situation over a holiday. Because that’s normal behaviour and empathetic and reasonable.

Not a big bird…but I was tickled when a boarder sent me this picture. I have a bird whispering fjord
I had a gelding that was terrified of poultry, chickens, turkeys, and especially guinea fowl.
Too many stories to tell… He was tolerant of song birds though.
When spring shedding of winter coats began I always groomed him and the mare in the paddock after I noticed the birds were waiting with interest in the trees for the horse fluff to fall so they could use it for nesting.
I had both of the horses tied and never saw one on him, but while I was grooming him a bird that apparently could not contain its glee over the supply of fluffy nesting hair and couldn’t wait for the hair to hit the ground, landed on the mare’s croup and began (easily) plucking tufts of shedding hair.
The mare was nonplussed.
@skydy, that’s adorable! I see little nests incorporating mane or tail hair around my farm often, but I’ve never seen any birds go straight to the source.

we observers would notice and stop them.
So…
You & everyone at that barn can run as fast - or faster - as a trotting horse?
IME, walking after them stands a CHANCE of catching up, anything faster & they see you coming & put it in a higher gear.
ETA:
Coming back to add another “anecdote”
The only time I was able to catch up to a loose horse, was when the lesson pony where I boarded got out of his stall (tricky latch that kids hardly ever got done right) one Winter day.
Pony goes trotting out of the barn, taking an indirect route, around the front pasture, heading to the open front gate that leads to the road.
I never would have caught him (though I did observe his escape) if he hadn’t trotted onto a patch of ice.
Where he did a Bambi on Ice impression & stood splayfooted until I was able to walk up & get a halter/lead on him.
His face said he was pretty sure I had Majicked the ground he was on

but while I was grooming him a bird that apparently could not contain its glee over the supply of fluffy nesting hair and couldn’t wait for the hair to hit the ground, landed on the mare’s croup and began (easily) plucking tufts of shedding hair.
I love this description of the bird!
If you stopped responding, people would stop responding and the thread would die but for some reason you keep coming back and arguing with people. Honestly If I were your barn owner and I stumbled across this thread I’d give you your notice because for some reason this is still an issue for you.
I laughed out loud at that bird. It was a brave little thing. I was grooming my gelding about 12 feet away from the mare and the bird didn’t care, it wanted that gray mare fluff and it was determined to get it. These many years later it still makes me smile.
All the other birds waited patiently. I thought it was interesting that the little bird knew the horses were the source of the hair on the ground, but just couldn’t wait for me to remove the hair from the mare.
Maybe it was especially fond of gray for decorating purposes and wanted to use that color before any of the other birds did.
Loose horses can hurt or kill innocent people if they get into the road and cause a car accident or get hit. It happens. I wouldn’t want that on me just because I wanted Dobbin to free range.
Never stand in front of a bolting horse. Even if you know the horse.
Such a great point. So utterly irresponsible to do that with open gates. Complete lack of genuine horsemanship that, as well as a complete lack of social responsibility. I cannot fathom grown-ass adults who subscribe to such majikal thinking that they believe their horses are all mystically trained to stay on the property, will NEVER go off it no matter what the provocation, and, to cap it all off, think they can stop a horse that bolts (or even briskly trots) away.
If one of those free grazing horses grazed over a yellow jacket nest or even just got a good sting or a fright and bolted - so irresponsible to the horse and, as you point out, to anyone unlucky enough to be on the road at the time.
Black stallion syndrome drives me insane. And acting as though you are superior to people who keep their gates closed and their horses safely pastured is just dumb.

IME, walking after them stands a CHANCE of catching up, anything faster & they see you coming & put it in a higher gear.
This reminds me of the time I came off my horse on cross country at an event. He started to jump the double log oxer, changed his mind and dropped his front legs between the logs. His nose just about touched the ground on the far side of the second long, and I slid down his neck, somersaulting over his head and taking the bridle with me. Before I could get up, I heard him scrambling over the jump, and I stayed tucked in a ball to stay out of his way.
He paused, looked around, determined the trailers were “that way” and walked that way. A couple of people with arms spread wide walked towards him from either side further up the course. When it seemed that they would block his path, he picked up a jog (yes, a tiny jog trot) and the two people were able to touch the saddle, but not stop him as he transitioned back to walk and continued on his mission with me trailing along behind.
That’s a hilarious image! My horse spun out from under me on XC because someone started a chainsaw next to the galloping track. I landed on my feet running, but he was gone like a rocket back to the trailers.
When I caught up to him, someone had snagged him, but everyone was impressed by his speed. I finished the course but, naturally, I was eliminated on time faults. Too bad, because he was second after dressage.
He was what I would call highly trained, also.
I remember when I was a child, my parents would take us to the Presbyterian church on most Sundays.
There was a young couple, she was in a wheelchair pushed by her husband. She was obviously significantly impaired (with what I now realize was a TBI and apparently other severe injuries) and unable to use the chair on her own or communicate clearly with speech.
I asked my Dad what was wrong, what happened to her, and he said that a year before, the couple were on their honeymoon and collided with a loose horse on a highway.
I had already been taught that gate latching was of the utmost importance where horses were concerned and that a loose horse was an emergency, especially if it could leave the property which should not happen (back to the importance of latching gates.)
The sight of the woman in the wheelchair really affected me and brought home the importance of always closing gates. Being a child, I had never really thought about anything but the possibility of an injury to the loose horse.
I learned the human cost that Sunday, and it was tragic.
That reminds me…the only creature that has seriously chased me while I was riding a horse was a very angry yellow jacket.
I had someone else’s cows on my property today. Why, might you ask? Because apparently my cousin pulled back my fence to create an opening for deer to come through.
I’m quite frankly, livid, because he didn’t ask me if it was okay to do this. The whole point of the fence is to keep the feral/random donkeys and cows out because I know the neighbor is cavalier about coming to get them.
If three cows could come in, you bet my horses would try to squeeze out if they got out of their regular paddocks. This is right next to a service road where it wouldn’t take long for a horse/cow/donkey to go splat……and they have before, especially at night.
They trashed the deer feeder.
Thank you for sharing. Everyone can use a reminder like this. Imagine how you’d feel if an accident led to your horse getting out and the result was this. That someone would set the stage for horses getting out and think it’s cool and that they can stop a loose horse under any and all circumstances from leaving a property is insanity - breathtaking arrogance and lack of concern for the animals themselves and other innocent bystanders.