Deficiency of niacin (nicotinic acid) gave a
high percentage of leg deformities, especially associated with medial deviations of the tibiotarsal
and tarsal-metatarsal bones as shown by Summers et al. (1984). Corn-soybean diets
in particular are low in niacin (Ruiz et al., 1990). Also riboflavin (Vitamin B2) deficiency
is associated with leg deformities and particularly curled-toe paralysis, a specific symptom
caused by peripheral nerve degeneration, in which the chicks walk on their hocks with the
toes curled inwards (Gries and Scott, 1972; Summers et al., 1984; Jortner et al., 1987).