hypothetical breeding question
 

Ok, So I have a bay mare, not color tested so i don't know her genes. I'm playing around with the color calculator just for the fun of it. So say i bred her with this random horse I found on dreamhorse.com(I wouldn't, but this horse is the color I would want to bred to if I ever did) DreamHorse.com Horse ID: 1113271 - Check Out My Jeans
under his description it says High Percentage Dun Factor Producer, Homozygous Black, Homozygous Tobiano. So i'm not sure if he homozygous dun or red(as the color calculator asks. So given what I know, my the possibilities are

Bay Tobiano Bay Dun Tobiano Grullo Tobiano Black Tobiano Red Dun Tobiano Chestnut Tobiano

So that would mean my mare would be guaranteed to produce a tobiano foal? But I thought there was no way to guarantee a colored foal when the mare is solid, especially when she is not even tested? I am so confused with this stuff lol.
Please don't critique the stud as I was just using him as an example for his color.

If he is homozygous for tobiano, then that means that he will pass on 1 copy of the tobiano gene to the foal 100% of the time. That being said, however, having the gene does not guarantee color on the foal. They can carry the tobiano gene and still have no more white than a star and one sock.

Yes, you would be guaranteed to get a tobiano foal...now, rarely, tobiano occurs in "slipped" version, meaning that there are not visible spots and the horse does not appear tobiano...but odds are still very good that you would end up a spotted foal. You would also be guaranteed a black, bay, dun, or grullo base color with that pairing.

Isn't that colour calculator a great site!!!!

Color Calculator

I am hoping for something other than a bay next year breeding my red dun mare to my bay stallion....lol