[nrhareiner]

I was once looking at a lady's buckskin stallion (who should have been a gelding) and she told me you can't breed palomino to palomino because you'd get a lethal white, I'd already desided she was a flake, I just nodded and moved on.

I know several older horse owner/breeder who thought this back before the actual genetics where known.

Also up until a few years ago AQHA would not register a double dilute so you would not want to breed 2 dilutes and take that chance.

 

[nrhareiner]

The sire was probably a Perleno not a cremello. Which means he is black based with 2 cream genes.

Your red dun mare is Red based with the dun gene.

Black is dominant to red so red will hide behind black.

So the foal can most certainly be a Dun. Basically the foal is Ee A? Dndn

Also breeding to a cremello dose not mean you will get the color of the other horse. It simply means that EVERY foal by/out of the Cremello will have at least one dilute.

 

[nrhareiner]

Double dilutes suffer from sun sensitivity and an increased risk of skin cancer and vision loss. THAT'S why (sensible) people want to avoid breeding them.

No more then grays or paints with a lot of white.

As to the sight loss. That is anouther one of those rummers. There are certain lines and certain breeds that are more prone to blindness but has nothing to do with color.