What does "tight hinded" mean in reference to show lambs?

On a recent road trip, I passed through parts of the Midwestern and North Central regions of the country that I’d never seen before. I noticed many unusual things for sale at routine gas station stops—unusual to me, anyway. One of those things was a lamb tube, an item of a kind that I had just flat never contemplated before in my life.

I almost bought one for $14.99 just for the novelty of it, but in a store that also sold spurs and bullets, I thought I was better off not to offend the locals by treating their gear as a curiosity.

Once back home, I looked some of those things up. (Elk honey, anyone?) Here’s what I found to describe lamb tubes:

“A special stretch blanket specifically for show lambs. Keeps lambs tight hinded and clean till show time.”

All the descriptions I could find used that same term.

I then searched as diligently as possible but was unable to find any definition for “tight hinded.” Who can tell me what that means?