Room to run is the real hazard
The typical Paint Horse problem on fireworks night is not temperament — Paints are level-headed stock horses — it is geography. A Paint turned out in a large pasture has a long run-up, and a horse who panics at a gallop arrives at the far fence carrying serious momentum. Horses are hurt on fireworks night by the fence they did not stop for, not by the noise itself. Everything in your plan should therefore shrink the space and shorten the run before the first bang.
Move him close, and keep a friend with him
Bring your Paint into the smallest sound paddock you have, ideally the one beside the barn that he already knows, well before dark. Put his usual companion in with him — a settled herd mate is a brake on panic, because a horse checks his companion's reaction before committing to flight. Feed hay in the paddock so the evening starts with heads down and mouths busy, and fill the water trough; a horse who has just drunk and eaten is physiologically calmer than a hungry one waiting at the gate.
Fence power, checked in daylight
If the paddock runs on electric tape or rope, test it that afternoon with a fence tester rather than trusting the energizer's clicking. A weak battery or a strand shorting on wet grass gives you a fence that looks fine and stops nothing, and a startled Paint leaning through tape can take the whole line down and tangle himself in it. Walk the boundary for fallen branches and loose posts, and chain the road gate rather than relying on its latch alone. While you are out there, check the trough position and the shelter roof too — five quiet minutes in daylight saves a midnight scramble in the dark.
If he is stabled instead
A Paint who is normally out may fret more in a strange stable than in a familiar small paddock — choose the option he already knows. If he does come in, deep bedding, lights left on, and a radio at yard volume soften both the flashes and the bangs, and a hay net keeps him occupied through the worst volleys. Either way, one calm visit during the display, from the fence or the door, reassures him more than repeated anxious checks. If the display runs long, a second hay net offered partway through the evening gives him a fresh job just as the novelty of the first one wears off.
The dark-road problem
A loose horse on an unlit road at night is the outcome every part of this plan exists to prevent — drivers cannot see a dark bay-and-white horse until far too late. Check him first thing in the morning for cuts, a twisted shoe, or stiffness from a scramble, and call your vet the same day if he is lame, off his feed, or showing colic signs. And know your backup before you need it: through KinsLe's Circle of Love, your free account connects you to nearby pet lovers, so if a frightened horse does get out, the neighbours most likely to see him can be watching for him and can reach you quickly.