Sorry, I tried to get pictures, but they did not go thru. A friend sent pictures of a friend whose Reese Hitch bumper pull had a stress fracture that broke while the trailer was loaded with 2 horses on a major highway. Trailer overturned, horses and people O.K. Break away worked, but not effective. Very clear picture of hitch break, as well as trailer and horses. I will try to figure out how to send this weekend.

Here is the trailer, horses got out with apparently minor injuries.

Do you know what the weight rating of the receiver and ball were? Thankfully all were OK, which makes this a good situation to study.

I don't have those details and frankly the owner is still shook up over this.  I know he has traveled hundreds of thousands of mile over the past several years with his horse.  I don't know how many rigs that was.  I believe he was pulling with a motor home.

This is a great time to remind everyone that each component of the towing system has a rating. The piece that broke here is generally known as a "ball mount". This one (from the little pic) looks like a 6" drop, in a standard duty version, notice the small shank hole for the ball. Many brands would rate theirs in the 4-5000# range. This trailer is obviously a 3H BP with oversized dressing room, 8' wide, with a hayrack. It could very likely run in at close to 10,000# loaded. As I said, I don't have access to all of the info- but it is imperative to clearly check every link in the chain. I've often seen a 5,000# light duty mount with small shanked ball (rated at 5,000#) pulling 8,000# of trailer behind a 1 ton truck. Lots of trailer, plenty of truck, but not such a great connection.

And yes- I am very relieved no one was hurt in this crash. It could have ended up a lot uglier. Another thing for us to be thankful for this time of year.

that is an excellent point RT.