Areveruz, I missed that too... Condolences for your lost. That's awful!
Ask me how I know what it's like to see two of your horses/the trailer careen past your tow vehicle and proceed to gain speed across the grass median into three lanes of oncoming traffic on a busy interstate. .
Wow... sounds horrible! Don't you have a emergency break cable attached to the car that immediately pulls the hand break of the trailer if it detaches from the hitch? That's mandatory here.
I've lost a trailer once while crossing a rail way, the hitch comming off over the bumps (and due to the break cable, it stopped immediately ON the rail way crossing). Luckily, the trailer was empty and I could push it away quickly
"Yeah... no, that's not clumsiness, that's just being topographically challenged" ~ Noreaster