I don't know the answer to Shaun's question but I suspect it could be a transfer of usage from agricultural to sporting events - although there was a theatre (flicks) in Batley with a scratting shed.

A cry that came out from Lawkholme's scratting shed was - "come on the steam pigs" - ie a hot scrum on a frosty day

Years at KBGS e.g. 1958-1964 (optional) 1952-60

Current location (optional) Nirvana

Hi Shaun, a furtherance of the man made o' band was the addition "tied up wi string."
I well recall the use of the term "shook" to describe a person of questionable sanity or normality.

Years at KBGS e.g. 1958-1964 (optional) 1952-60

Current location (optional) Nirvana

Others have scratched their heads over your question Shaun:

http://i.rlfans.com/forums/viewtopic.php?f=15&t=564118

Years at KBGS e.g. 1958-1964 (optional) 54-59

As a lifelong poultry farmer, a "Scrattin" shed would be just that ,a covered ,dry , shed, for the old hens to "Scrat" about in .No doubt Agricultural origin.

Years at KBGS e.g. 1958-1964 (optional) 43-46

Current location (optional) Tasmania