He returned to his father's house, and studied the engravings of Callot and Le Clerc, whose peculiarities proved a great influence on his style.
He soon gained a great reputation for small landscapes and sea-pieces with figures, and for fairs and peasant scenes in the style of Ostade, Berchem, and Poelenburg.
This version of events was, however, disputed by Noel Desenfans, who attributed Ferg's difficulties to a head injury caused by a blow from falling roof-tile, which rendered him unable to paint.
Ferg also executed some etchings, mostly landscapes of a small size with figures and ruins; also a larger plate of Boors Carousing, in the style of Ostade.
[3] John Thomas Smith[2] and some later sources[3] refer to Ferg working as a decorator at the Chelsea porcelain factory: this cannot however be true, as it was not in production until after his death.