A horse's mouth lathers because it is usually do to relaxation of their jaw. It can also be a sign of tension and damage to the horses internal system ( Usually only seen in rollkur trained horses).
It is a possibly, but there are no reported cases of it in horses.
A plain snaffle or a happy mouth.
fod
Their mouth....
A horses bars are the toothless spaces in it's mouth, where the bit is placed.
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.
The bit
it is called a bit
hold it near the horses mouth but don't bang his/her teeth
you got it straight from the source
You may be thinking of the Horses of the Carmargue at the mouth of the River Rhone in the South of France