Sebastopols have been called the 'pantomime goose' because of their fancy feathers. They have a curled feather mutation which gives the birds a fluffy appearance. The shaft of the longer feathers splits and the vane is fluted. So, the flight feathers are soft and trail to the ground. This would be a lethal mutation in the wild because the birds cannot fly.  The birds illustrated  are known as the  curled feather variety.

Birds which are heterozygous for this mutation have curled feathers trailing only from the scapular (shoulder) and thigh coverts. The rest of the body feathers appear normal. The 

flight feathers are slightly fluted, and the tail feathers are also affected. This type (not illustrated) is known as the smooth breasted. 
The best breeding combination is a mixture of the two types; such a pair will breed both types. It may also help counteract the tendency for angel wing in this breed. However, the weight and length of the flight feathers often tends to pull the wing joint outwards. 
The curled feather and the smooth breasted are both standardized in the UK. [The curly feather type is no longer called the frizzle because the gene behaves differently from the poultry frizzle gene].  
In Germany it is just the smooth breasted that is standardized.  In the USA, it is the curled feather variety. 

Sebastopols are a light weight domestic goose weighing 10-16 lbs. Temperament varies depending on the strain, as does egg-laying capability. Some strains lay up to 40 eggs per year. Imported from the port of Sebastopol, they were figured and described in the Illustrated London News in 1860. Birds like these were reported from the countries surrounding the Black Sea, and the lower Danube - hence an alternative name: the Danubian goose. 

How to Sex Sebastopols
 Like all white European geese, white Sebastopol goslings are auto sexing. In the picture (below left) there are two females and one paler male (in the middle). The females are darker because they only have one dilution gene (which is sex-linked). The male has two dilution genes so he is paler. They also have the  'spot' gene which gives the 'saddleback' appearance in the fluff. In the feathers, dilution and spot together make geese white. 

Also, the spot gene is revealed  in cross-breeding if the dilution gene is bred out. So, Sebastopols are now also in  buff back and grey back (saddleback, pied), and even whole grey. Blues may also have been bred. 

We occasionally have Sebastopols for sale. In high rainfall areas they should be housed at night (rather then stay out in a fox-proof pen) because the back feathers do not give such good protection as normal goose feathers. Also,to keep birds in good condition they must have clean paddling water.