I bought a mini sized muzzle for a miniature donkey. I didn't have it on him 24/7. So far it has been sturdy enough, but my donkey is very resourceful and will rub it along the ground ground and anything he can to rub it off because he likes to munch. I have to constantly adjust it to keep it tight enough that he doesn't get it half on and half off. Numerous times he has managed to get it in his mouth and then chew on it for a few hours..top or bottom. The stitching really could stand to be of heavier thread. I've already had to have it restitched once and I purchased it 4 months ago. Keep in mind he does not wear it 24/7. It is a good muzzle and design if you have one that doesn't mind wearing it, but for one that is determined to eat...I have to find another design.
We ordered two of these for our 2 year old colts. We got the "horse" size. Unless your horse is a draft breed, this muzzle will not fit. It's large enough for both our horses' nose in one. It would be nice if the makers of the muzzles would make them in more sizes like 12 inch, 12.5, 13, etc.. so they would actually FIT an individual horse's muzzle. They are supposed to fit snugly so good luck getting one that fits. I guess we'll try the yearling size because we are desperate for something to limit grass intake.