What Nasser was saying is that " to have a grey foal, one of the parents has to be grey." That is a correct statement.
This does not mean that the reverse is true, that you have to have a bay parent to have a bay foal, you don't. Two (heterozygous) grey parents have bay (or chestnut) foals all the time, and it is not unusual. When this happens, it means you have 2 heterozygous grey parents, and neither one passed on their grey gene. With 2 heterozygous grey parents, you have a 25% chance of getting a non-grey foal.
With 2 bay parents, you have 0 chance of getting a grey foal.
Thank you, Laurie, for taking the time to post that very interesting information, but I think people have misunderstood my post asking about my filly's color. lol I know that two grey parents can produce any color, depending on their genetics. I also know that one parent has to be grey in order to produce a grey foal and that two "solid" colored horses will never produce a grey, as well as the fact that two chestnuts will always produce chestnut (unless one of them is actually a "silver bay" which may appear chestnut, but will be genetically bay and thus, can produce a bay foal).My filly has one GREY parent and one BAY parent.
She appears to be bay, but of course, she could just be bay turning grey. I guess I should have asked the question, "What tips can you all offer to figure out (by just looking at the foal) whether a foal born bay - with at least one grey parent - will turn grey or stay bay?"
I have always gone by these rules when figuring out the color of foals born to at least one grey parent:
1) A foal with white hairs around the eyes, nose, or around the tail will be grey;
2) A bay foal born with black legs will be grey;
3) A bay foal with black around the eyes will likely be grey.
My filly does NOT have black legs. Her legs are, in fact, fawn colored except for the very back of the fetlock where there is a tuft of dark hair.
My filly does not have white hairs around the eyes, muzzle or tail - YET.
My filly does have dark hair around her eyes and down her back.
What are some tips some of you have for telling whether such a foal will stay bay or turn grey (other than waiting it out! lol)?
Thanks for the input from all of you who have posted so far.
Susan, I sure hope you make the Paris trip this year - it will be FUN!