Green’s Dictionary of Slang

1. a guinea-fowl.

1887

Temple Bar Mar. 333: It’s a sin to think of the money you’d be spending on girls and things as don’t know a hen’s egg from a galeeny’s [F&H].

2. any sort of fowl.

1812		Vaux Vocab. of the Flash Lang.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.