Color Breeding

If the paint stud is homozygous for his markings then the foal WILL Have markings. If he is not homozygous, then there is 50/50 chance of the foal being marked like a paint (and 50/50 chance he will just be ordinary coloured).

If the dam only has bay/brown in her colours, and no hidden chestnut, then you have no chance of getting a chestnut foal (with or without paint markings). If both sire and dam are hiding chestnut genes, then they could combine to produce a chestnut foal.

Grey is on a seperate chromosome, so even if you can figure out whether or not the foal will be paint, or not paint, or chestnut or bay or brown - the grey is dominant. And it is entirely dominant, so mum only has ot pass down one grey gene (dad doesnt have one at all, if he did he too would be grey due to its dominance).

If mum is homozygous for grey, then she HAS to pass one down to foal and the foal WILL end up grey itself. If the mare is only heterozygous for grey (eg has only one grey gene)then there is a 50/50 chance of her passing it down to the foal or not and if it is then it will override all the other colour p[ossibilities in the end anyway. Eg the foal may start out a bay paint, but will be 'going grey'. Or it may be a solid chestnut to begin with, but will be 'going grey' (therefore classified as grey).

I had a grey arab welsh cross mare. I bred her to pinto that was homozygous for his markings but I didn't know if he was homozygous for his black colouring. My grey mare may have been chestnut before she went white (but I didn't know for sure, I only know that she had to have at least one chestnut gene because her previous foal had been born chestnut, so the foal got chestnut genes from both her sire and dam).

Anyway not knowing the mares history, the possibilities for the foal were