Breeding a donkey and a horse makes a mule, and you will end up with a colt like any equine.
Donkeys and horses are not from the same species because of this: In sexual organisms, two organisms belong to the same species if they are able to breed and have fertile offspring. Although horses and donkeys can have mules, they are infertile, so they are two separate species and the mule is a hybrid.
These is no special name for a donkey house. Perhaps a stable where horses, mules and donkeys could be found.
I'm pretty sure they use donkeys. This is correct, both Greek and Romans used donkeys as well as horses/chariots
Yearlings
It's still just called a 'horse', because horses and ponies are the same species, it's just that ponies are smaller and tend to have different proportions as a result.
Donkeys are really called donkeys! Unless you are asking for their Latin name, which is Equus asinus.
Donkeys belong to the odd-toed ungulates (horse, tapir and rhino families), also called the perissodactyls. This group, in turn, is related to the elephants and the sub-ungulates (sirenians and hyraxes). The horse family itself is a genus called Equus and the Linnaean name for the donkey is E. asinus. The closest relatives to the horses are the tapirs, which the late Barbara Woodhouse described as "prehistoric horses".
All donkeys have crosses on their backs.
The Indiana Colts
Yes, A jack is a male donkey. A Jennet is a female donkey. They mate and make more donkeys. A Jack can also mate with horses. They produce a mule. This is hybrid off spring is 99.9% sterile. Blue Moon is the name of a rare exception. I believe she is located in PA. and looks like a mule.
Foal is already the name used for Young horses. There is no Point in saying a Young foal, it's like saying a Young baby.
Colts aren't in a family. They are the name of a young male horse, under the age of 4. Sometimes all baby horses are called colts, but the proper name for a male baby is colt, and the proper name for a female baby is filly. When they are age 4 and older, the male is called stallion (stud if he is used in breeding) or gelding if he has been neutered, and a female is called a mare.