Wouldn't Back on Track products have a different effect than a poultice? They're advertised to reflect body heat back at the horse, whereas a poultice should be drawing heat out if I'm understanding correctly.
BOT reflects the infrared waves, increasing circulation but not "heating" anything, if that makes sense? So the increased circulation helps prevent stocking up and any inflammation that might occur after a hard workout. This past winter my mare's legs started blowing up like stove pipes, for seemingly no reason. There wasn't much heat, and she wasn't lame at all, but after trying standing wraps for the better part of a week and them having absolutely no effect on the swelling, I threw the BOT quick wraps on overnight just to try, since what I was doing obviously wasn't working. I was SHOCKED when the next morning my mare's legs were tight and cool. This happened a few more times over the winter, and the BOT would take the swelling right back down.
At first I thought that BOT would just "heat up", but after using them a bunch, it actually does the opposite for legs. I prefer them over standing wraps now, at events. It's all personal preference though. There are a few situations where I would choose to poultice, but I've not run into them with my current horse.
So, say I wanted to use a poultice on my mare after a hard workout. How long would I need to leave it on? I can't leave it on overnight because my mare goes out in a pasture... would it be useless to just put it on for a long trailer ride home? (say, 2 or 3 hours)
After hard workouts on most horses the will use rubbing alcohol on the legs & then wrap Or the poultice gook, ICE pack stuff. Its all for soothing the muscles and/or draws out heat. Sometimes they will use Tarr on the horses bulbs & hooves for heat drawing salves. Even pack the hooves with paper, poultice & tape the hoofs for the night.
The paper is normally wetted & then the poultice is applied, it keeps it wet longer for extra draw & air. It eventually dries & falls off when the wrap is taken off in the morning.
The plastic is used to keep the leg airtight, this allows the alcohol to help keep it in & slow circulation.
In some horses they will cold hose for 20 min with hooves in buckets of embsum salt.