Isidore of Seville, Etymologies 12.7:
The cock [gallus] is named after castration; for among other birds, it alone has its testicles removed, and the ancients used to call eunuchs cocks [galli]. Just as lioness is derived from lion, serpetness from serpent, so too is hen (gallina) derived from cock (gallus). Certain people say that if its limbs are mixed with molten gold, they are consumed entirely.
Gallus a castratione vocatus; inter ceteras enim aves huic solo testiculi adimuntur. Veteres enim abscisos gallos vocabant. Sicut autem a leone leaena et a dracone dracaena, ita a gallo gallina. Cuius membra, ut ferunt quidam, si auro liquescenti misceantur, consumi.
Galli, eh? *Cybele intensifies*