As a Professional Equus breeder I think u should always tame both genders and breed them and even though it usually takes a long time for the equus to be born it still is amazing when you imprint the equus fully it is one of the best things you can have.
It eats troodon kibble or rockcarrot then ride every time it is going to stop and do its animation you press 0 or right on the d pad and have rockcarrot or troodon kibble there then u have your equs. ;)
Found the Unicorn by Green on the Island. It will be all white and look like a sheep from a distance. In general, they seem to appear in groups of two or more. Move to a safe area or have an escort to clear the area of danger when taming!