What could "fermison" mean in this sentence?:
In 1370 Ralph Basset, who held lands in wardship of the heir of John Mowbray of Axholme, was ordered to allow the proctor in England of the abbot of Fécamp to exercise, among other rights, his right to 'five good bucks in time of grease (in gresso) and five does in time of fermison, all whole with their hides' in the woods of Stanherst and Rippefeld, a right that the abbot had going back to the time of Henry III.
— quotation from Edward III and the English Peerage: Royal Patronage, Social Mobility and Political Control in Fourteenth-Century England by J.S. Bothwell