There have been real hiring fairs well within living memory.Just before WW2, a friend of mine - now 85 - hired himself out at a hiring fair at Carlisle Market Cross. The usual contract was "a year and a day" including (both ends) the day of the fair. Full board was provided during the year and payment at the end of the contract. The employee then went back to the fair, got drunk and hired-on again.
Around the turn of the century, quite a few agricultural labourers from East Anglia were hiring on in Yorkshire as things were bad at home, and the pay was better there. That reminds me of one of the hiring fair songs "Yaddie Hughes".
Cheers!
Ian