Green’s Dictionary of Slang

roost lay n.

[SE roost + lay n.3 (1)]

poultry-stealing.

[UK]Lex. Balatronicum.
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.
[US]Matsell Vocabulum.
[Aus]C. Crowe Aus. Sl. Dict. 67: Roost Lay, stealing poultry.
[Aus]Argus (Melbourne) 20 Sept. 6/4: Among these small fry of the profession may be included the [...] beaker-hunter, and the snagler, who are both on the roost lay, or poultry stealing.