There doesn't seem to be such things but my rooster has one! No, really, he has a fairly low comb, no tall spikes, and I guess it would be considered single. But when looking at him straight on, his comb has a circle. It looks like a naval, or a tiny donut. What would that be considered? He's a mutt, maybe jap bantam, but who really knows.
sounds like an inverted comb to me... it's when a comb is squished in instead of out... you can fix it, and if you fix it early, it will be fine... i put some lotion on it for an hour or so and massage it... then grab a point and pull it all out... then if it's really bad, i get some popcicle sticks, break it in half and tape it on each side pressing it together... that way when he's older, it's not all fat and hallow like.. then when you dub it, it bleeds a ton and is a huge hole instead of a sharp nice job...
