Note 315 — SCENE IV.
Reading edition
The metaphor is taken from a cock, who in his pride prunes himself, that is, picks off the loose feathers to smooth the rest. See notes by Dr Johnson and Mr Steevens to "First Part of King Henry IV.," act i. sc. 1.
The previous metaphors and phrases are from falconry, and probably the allusion is meant to be continued here: a hawk may be said to prune itself sleek just as well as a cock.—Collier.