c- Recessive White
I guess I overlooked recessive white!
Recessive white (c/c) is an autosomal recessive gene that turns a bird's plumage completely white regardless of its genetics. Even though it doesn't change the skin and eye color, it is considered a form of albinism. Recessive white Silkies, for example, may have black skin, eyes, and bones but white feathers.
Recessive White is a mutation of the TYR (tyrosinase) gene. Other mutations on the C allele are ca (autosomal albino) and Red Eyed White (cre). These are both very rare. Red Eyed Whites have very dark eyes and don't look very different from regular recessive whites.
Recessive White removes most of the pigment in birds but some grey flecking may be present. Solid white birds are more likely to be Recessive White than Dominant White since Recessive White dilutes pigment much more strongly.
Knowing what genes are found in the breed can help you infer whether a chicken is dominant or recessive white.
You can't determine the genotype of a Recessive White chicken by looking at it. Knowing what breed it is and knowing its genetic history could provide an educated guess. A Recessive White bred to another color of chicken will reveal some the genes that are being masked by Recessive White.