The classic "smooth breasted" white Sebastopol is curly all over with just a smooth breast, as described and illustrated by Pete55.
I think were the confusion comes in is, there are so many colored Sebastopols out there now that have varying degrees of smooth
and curly feathers that can range from almost all smooth to just smooth breasted so people need to be specific when
inquirying or describing especially when in the case of a purchase or a sale.
"Smooth" can mean many things depending on who you are talking to.
From all I can gather...aside from Dave Holderread developing colored Sebastopols most of the established U.S. Sebastopols breeders would never
dream of using a smooth breasted Sebastopol but I'm beginning to suspect from what Pete has told us regarding the UK Sebs not having twisted
wing tip (not to be confused with Angel Wing) that breeding curly x curly MIGHT be contributing to the common problem of TWT because smooth
breasted is favored in the UK and curly x curly breedings frowned upon.
Dave H has said breeding smooth x curly helps prevent wing disorders although I've personally had 2 - 3 cases of really on set TWT in my
smooth gander's offspring so I don't know what to think.
Since I have a small operation I can't really determine if this is the case or not but it makes sense to me that TWT is the result of the curly feather mutation
and/or breeding curly x curly.
As for using smooth individuals my best curly saddleback goose
has a very smooth father so the smooth gene does not necessarilly hinder the production of quality of long feathering.
Never-the-less people generally want curly not smooth Sebastopols so keep that in mine that when using smooth breeding stock
that around 50% of your goslings will be smooth to varying degrees. If you are just breeding a few pets and selling to a pet market
you'd be better off having all curly breeding stock.
Hope this helps and please join our specialty breed forum to learn more about Sebastopols.
My smooth saddleback gander.

Smooth gander's son

Smooth gander's daughter

Edited by Cottage Rose - 2/29/12 at 9:32am