Green’s Dictionary of Slang

bit by... phr.

drunk; in combs. below.

In phrases

bit by a barn-mouse (also bit by a barn weasel) [? the barn-mouse consumes barley, from which beer is brewed]

[mid-17C–early 19C] drunk.

bit by the brewer’s dog

[1940s] (US) drunk.

bit by the tavern bitch (also tavern bitch has bit him in the head)

[17C–18C] drunk.