Feather
Pied / Mottle => mo (pi)
The pied pattern is recessive, black and white as in Exchequer Leghorn. Research has shown that the pied and mottle patterns are due to the mottle gene. It is no longer accepted that 'pied' is a distinct gene from mottle, however it is not known why the mottle gene causes the pied pattern in some birds and the typical mottle pattern in others. Mottle causes a white tip at the distal end (end farthest from the skin) of the feather. Chicks with extended black and mottle (E/E mo/mo) as in the Exchequer Leghorn will often have black restricted from the belly and sometimes the head.
Erminette => no symbol
Black spots and flecks, variable black and white feathers, similar to pied.
Mottle => mo recessive.
Makes a white tip on end of feather. Changes a black bird to Mottled and a Buff Columbian to a Mille Fleur. Dilutes epidermal melanin. There may be several alleles corresponding to this locus or non-allelic modifying genes.
=> Mo+ Wild-type gene. Dominant. Lack of mottling.