1) The usual explanation is that a ‘frank’ was a stall or sty in which hogs could be fattened.
The following sequence of entries in the accounts of Whitby Abbey suggest that in this case it referred to the animals and not the enclosures in which they were fed: 1394-5 It. pro frankis venditis apud Semar xliiijs: It. pro ij frankis vend. apud Hakeness xlvjs viijd: It. pro j franke vend. Celerario Coquinć xvjs.