from The Century Dictionary and Cyclopedia
- n. A large-sized game-cock.
Sorry, no etymologies found.
As for the main Sir Peter had meant to fight with his Flatbush birds, we tried a shake-bag, stags, which, though fairly matched and handled by past masters, billed and pecked and panted without a blow from wing or spur, till we understood that the heat had stunned them, and so gave up to wait for cooler sport.
Quin) against the best shake-bag of the whole main.’