Most likely one, rearly does a mare have twins and survives.
There are zebra foals and pony foals, so yes.
Foals
A Baby horse is called a "foal". Male foals may also be called "colts" and female foals may be called "filly", however the generic term is "foal".
The most general answer for the foals born to a mare or stallion are as follows. Dam: is the word for a mare or female horse producing foals. The foals she produces are called her "produce". Sire: is the word for a stallion or male horse who has bred mares. The foals produced by a stallion are call his "get". (The stallion "gets" the mares in foal so the foals produced by him are his "get".)
No..
No. It isn't possible. A horse can only have up to two foals and if that happens it is rare that one of them survive and even rarer if both survive.
Yes, but pasteurized cow's milk is not ideally suited for horse foals. There are products on the market designed for foals or there are recipes to enhance goat's or cow's milk to increase it's suitability for foals.
A baby horse is a foal. Foals grow to become adult horses.
The way to get foals on Farmville, is to, you have to have full grown horses, to put in your horse stables, if you have horses in your stables, you can have chances of having foals. Another way to get foals is to check out your farmville friends profile pages.
A mare or stallions foals are called 'Get' collectively. They can also just be referred to as foals or offspring.
A "Dam" is the term used for a baby horse's (foals) mother. A foals father is called the Sire.
The youngest horse would be one of the foals that were miscarried and never even born.