Green’s Dictionary of Slang

mow-heater n.

also mow beater
[the drover’s habit of sleeping on hay mows + ? drover’s ‘heating up’ of the mower n.’s behinds as he uses his stick to guide them through gates, down lanes etc.]

(UK Und.) a drover.

[Ire]Head Canting Academy (2nd edn) n.p.: Mow-heater Drover.
[UK]B.E. Dict. Canting Crew n.p.: Mow-beater A Drover.
[UK]J. Shirley Triumph of Wit 195: The mow-heater pikes off with the Mows [The Drover goes away with the Cows].
[UK]New Canting Dict. n.p.: mow-heater, c. a drover.
[UK]Bailey Universal Etym. Eng. Dict. [as cit. 1725].
[UK]Scoundrel’s Dict. 17: A Drover – Mow-beater. [Ibid.] 21: The Mow-beater pikes off with the Mows.
[UK]Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Mow Heater. A Drover: from their frequent sleeping on Hay Mows.
[UK]Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn) n.p.:
[UK]Lex. Balatronicum [as cit. 1788].
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue [as cit. 1788].