The hole is a "breathing hole" of sorts. Breyer does this so that air does not expand or contract within the model due to heat and cause damage to it.
http://www.breyerhorses.com/faq/#Q13
Yes, heat can cause "bloating" in plastic model horses. As the horse heats up, so does the air inside, causing it to expand. The small hole sometimes found near the mouth is an attempt to avoid bloating by allowing the air to escape in the case of expansion.
It usually means you have something on the corner of your mouth.
It is a possibly, but there are no reported cases of it in horses.
A plain snaffle or a happy mouth.
The mouth.
Their mouth....
fod
A horses bars are the toothless spaces in it's mouth, where the bit is placed.
If you have a cut on the corner of your mouth that won't heal, you should see a doctor. They can determine the cause of the lack of healing.
A bit is metal bar that is on the bottom of the bridle. This fits inside the horses mouth, behind the teeth, where there is a gap.
The part of the tack (harness) that fits in the mouth of a horse is the bit.
a kufuzelanter