Not every Sebastopol has the same distribution of curls

The Poultry Club distinguishes smooth-breasted and curly-breasted Sebastopols. In the smooth-breasted form, ordinary feathers remain on the head, neck, breast, and abdomen while long curls trail elsewhere. In the curly-breasted form, curled feathers extend over more of the body.

This distinction prevents one favored photograph from becoming an inaccurate definition of the entire breed. A smooth breast does not, by itself, disqualify an animal from the broader Sebastopol tradition. The source's identified form should accompany an image so viewers understand what they are seeing.

The club dates British standardization of the curly-breasted form to 1982 and the smooth-breasted form to 1997. Those are formal recognition events, not the first existence of curled geese. Keeping the forms and dates separate allows the library to discuss both inherited appearance and changes in how breeders described it.