Its treatment of course involves surgically removing the feather follicles but if the follicle is just cut off and the accumulation of keratin with the feather is removed, then there are chances of its recurrence unless the wide incision of the feather follicle is done. Moreover, if it carries genetically multiple affected feathers then surgery is not recommended. Its better to provide it a diet having following amino acids:
Methionine
Lysine
Threonine
Tryptophan
Lecithin that is an unsaturated fatty acid is also helpful in feather growth to take place well. Other essential nutrients to cure this problem are:
Adequate B vitamins,
Mineral food mainly zinc
Folic acid
Biotin