confused about the comb

[Kickin' Chickin']

This is a picture of my sweet Shirley. I though EE's had pea combs, she is the only one out 6 to have this type- why is that?Could her egg have been a "donation " from another hen to her mamas nest?

 

[fancyfowl4ever]

ees being crosses they can have any type comb. one of my ees had a rosecomb. I had plenty with single too.