Start with the floor, because everything stands on it
More trailer disasters begin under the horse's feet than anywhere else. Lift the mats and inspect the floor every season, and before any long trip press your own weight across it board by board — rot and rust hide under rubber matting until a hoof goes through at speed. Check the ramp hinges and springs lift and lower smoothly, the partitions swing and pin securely, and the breech and breast bars are in place and adjusted for this horse's length. A trailer that rattles, sways or has a partition hanging loose teaches a good traveller to dread the box.
Tyres, lights, brakes and the tow vehicle
Walk around the whole rig with the lights on: indicators, brake lights and number plate light all working, breakaway cable attached, safety chains crossed, and the coupling locked with the jockey wheel fully up. Tyres need tread, correct pressure and sidewalls free of cracks and bulges — trailer tyres perish with age long before they wear out, because they spend their lives standing. Test the brakes on the first quiet stretch of every trip. Check your mirrors give you a view down both sides of the box, because the first sign of a horse scrambling or a tyre failing is usually seen, not heard.
Load for the horse you have, not the schedule you want
Bed the floor so he can brace and urinate without slipping, hang a hay net where he can reach it without getting a leg anywhere near the string, and travel him in protective boots or bandages and a tail guard against rubs on the bars. Load with time in hand: a horse loaded against a deadline absorbs your tension and practises refusing. If he loads in a headcollar at home but travels in company or alone, set the partitions for the trip he is actually taking. Take water and a bucket on any journey beyond a short hop, and offer a drink at stops — many horses will not drink strange water, so on long trips carrying water from home is worth the space.
Drive like there is a horse in the back — because there is
Accelerate gently, brake early and take bends at the speed that keeps him standing without leaning on the partitions. Stop after the first short stretch to check through the groom's door that he has settled, then at sensible intervals on long journeys. If he scrambles, sweats up or stops eating his hay, something is wrong — pull in somewhere safe and look rather than pushing on. On arrival, rest him in the box for a few minutes before unloading, and unload in a secure area with the ramp fully down and helpers briefed.
Papers travel with the horse, every time
Health records, his passport details, your vet's number and the destination's address belong in the vehicle, not in a drawer at home — if you are stopped, if he is injured on the road, or if he has to stay overnight somewhere strange, the person helping him needs his history in minutes. Keeping that packet together in KinsLe's Pet Passport means his records are complete and current on the day you travel, whether the trip is a pleasure ride, a show or a midnight dash to the vet hospital.