E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Stalking-horse.
A mask to conceal some design; a person put forward to mislead; a sham. Fowlers used to conceal themselves behind horses, and went on stalking step by step till they got within shot of the game.
1
N.B. To stalk is to walk with strides, from the Anglo-Saxon stlcan.
2
He uses his folly like a stalking-horse, and under the presentation of that he shoots his wit.Shakespeare: As You Like It, v 4.