Agricultural baler, comprising: - a bale chamber having an inlet opening formed therein; - a feeder duct communicating with the bale chamber through the inlet opening for charges of crop material to be transferred from the feeder duct into the bale chamber, wherein the bale chamber has a bottom wall in which the inlet opening is formed, and wherein the feeder duct has an upper end facing generally upwardly and communicating with the inlet opening in the bale chamber and a lower end facing generally in a forward direction, the feeder duct has a top wall and a bottom wall extending between the lower end and the upper end of the feeder duct, said top wall providing an upper boundary of the feeder duct and said bottom wall providing a lower boundary of the feeder duct; - a plunger reciprocable within the bale chamber to compress successive charges of crop material received from the feeder duct to form a bale; - feeder means operable within the feeder duct to accumulate a charge of crop material therein and then stuff that accumulated charge into the bale chamber; - means (85, 87, 99; 185, 187) for moving at least one of the top wall and the bottom wall of the feeder duct relative to the other one of the top wall and the bottom wall of the feeder duct in at least part of the feeder duct; characterised in that - at least one of the top wall and the bottom wall of the feeder duct is divided in sections (59, 61, 71) along the length of the feeder duct; - said means (85, 87, 99; 185, 187) for moving at least one of the top wall and the bottom wall of the feeder duct are adapted for selectively moving said sections relative to the other one of the top wall and the bottom wall of the feeder duct; - for each pair of adjacent sections (59, 61; 61, 71): - adjacent edges (67, 69; 73, 89) of the sections are mutually attached such that when moving the sections (61, 71) adjacent edges (73, 89) of the sections remain adjacent to one another; or - said means (85, 87, 99; 185, 187) for moving are adapted to move the sections (59, 61)such that adjacent edges (67, 69) of the sections (59, 61) remain adjacent to one another; and - at least one of the sections (59; 61) is in the form of a door, said door section (59; 61) having at least one edge (67; 69) that is selectively movable away from an adjacent edge (69; 67) of an adjacent section (61; 59) in order to provide an opening between said adjacent edges (67, 69). - a bale chamber having an inlet opening formed therein; - a feeder duct communicating with the bale chamber through the inlet opening for charges of crop material to be transferred from the feeder duct into the bale chamber, wherein the bale chamber has a bottom wall in which the inlet opening is formed, and wherein the feeder duct has an upper end facing generally upwardly and communicating with the inlet opening in the bale chamber and a lower end facing generally in a forward direction, the feeder duct has a top wall and a bottom wall extending between the lower end and the upper end of the feeder duct, said top wall providing an upper boundary of the feeder duct and said bottom wall providing a lower boundary of the feeder duct; - a plunger reciprocable within the bale chamber to compress successive charges of crop material received from the feeder duct to form a bale; - feeder means operable within the feeder duct to accumulate a charge of crop material therein and then stuff that accumulated charge into the bale chamber; - means (85, 87, 99; 185, 187) for moving at least one of the top wall and the bottom wall of the feeder duct relative to the other one of the top wall and the bottom wall of the feeder duct in at least part of the feeder duct; characterised in that - at least one of the top wall and the bottom wall of the feeder duct is divided in sections (59, 61, 71) along the length of the feeder duct; - said means (85, 87, 99; 185, 187) for moving at least one of the top wall and the bottom wall of the feeder duct are adapted for selectively moving said sections relative to the other one of the top wall and the bottom wall of the feeder duct; - for each pair of adjacent sections (59, 61; 61, 71): - adjacent edges (67, 69; 73, 89) of the sections are mutually attached such that when moving the sections (61, 71) adjacent edges (73, 89) of the sections remain adjacent to one another; or - said means (85, 87, 99; 185, 187) for moving are adapted to move the sections (59, 61)such that adjacent edges (67, 69) of the sections (59, 61) remain adjacent to one another; and - at least one of the sections (59; 61) is in the form of a door, said door section (59; 61) having at least one edge (67; 69) that is selectively movable away from an adjacent edge (69; 67) of an adjacent section (61; 59) in order to provide an opening between said adjacent edges (67, 69). - adjacent edges (67, 69; 73, 89) of the sections are mutually attached such that when moving the sections (61, 71) adjacent edges (73, 89) of the sections remain adjacent to one another; or - said means (85, 87, 99; 185, 187) for moving are adapted to move the sections (59, 61)such that adjacent edges (67, 69) of the sections (59, 61) remain adjacent to one another; and - at least one of the sections (59; 61) is in the form of a door, said door section (59; 61) having at least one edge (67; 69) that is selectively movable away from an adjacent edge (69; 67) of an adjacent section (61; 59) in order to provide an opening between said adjacent edges (67, 69).