Green’s Dictionary of Slang

slingtail n.

(UK Und.) chicken.

1859

Matsell Vocabulum 81: slingtail Poultry.

In compounds

slingtail and galena (n.)

(UK Und.) a dish of chicken and pickled pork.

a.1790		H.T. Potter New Dict. Cant (1795) n.p.: sling-tail and galena fowl and pickled pork.
1809		G. Andrewes Dict. Sl. and Cant.
1821		Flash Dict.
1835		G. Kent Modern Flash Dict. 30: Sling tale and galena – fowl and pickled pork.
1848		Flash Dict. in Sinks of London Laid Open [as cit. 1835].