A harvester comprising: a pair of oppositely facing sidewalls; a pickup assembly; a bale chamber, positioned between the pair of sidewalls, comprising a crop inlet at the front end of the bale chamber, and an outlet at the rear end of the bale chamber; a crop supply chamber (200, 320), positioned between the pair of sidewalls and in front of the bale chamber, comprising a supply inlet (203, 323) at the bottom of the crop supply chamber (200, 320); characterized in that the crop supply chamber (200, 320) further comprising a movable control surface (204, 324) positioned within the crop supply chamber (200, 320); and in that the harvester further comprising a conveyor system, positioned between the front of the crop inlet of the bale chamber and the pickup assembly, further positioned below the supply inlet (203, 323) of the crop supply chamber (200, 320); wherein the conveyor system comprises a front roller, a rear roller, at least one conveyor belt, capable of endless rotation around the front and rear rollers; wherein the crop supply chamber (200, 320) further comprises a front wall (201, 321), a rear wall (202, 322), and a storage volume (210, 328); wherein the storage volume (210, 328) is defined by the space between the front wall (201, 321), the rear wall (202, 322), the pair of oppositely facing sidewalls, the control surface (204, 324) and the supply inlet (203, 323); and wherein the control surface (204, 324) is able to move to a higher position in between the front wall (201, 421, 521) and the real wall (202, 422, 522), thus increasing the size of the storage volume (210, 430, 528); and to a lower position in between the front wall (201, 421, 521) and the rear wall (202, 422, 522), thus decreasing the size of the storage volume (210, 430, 528). a pair of oppositely facing sidewalls; a pickup assembly; a bale chamber, positioned between the pair of sidewalls, comprising a crop inlet at the front end of the bale chamber, and an outlet at the rear end of the bale chamber; a crop supply chamber (200, 320), positioned between the pair of sidewalls and in front of the bale chamber, comprising a supply inlet (203, 323) at the bottom of the crop supply chamber (200, 320); characterized in that the crop supply chamber (200, 320) further comprising a movable control surface (204, 324) positioned within the crop supply chamber (200, 320); and in that the harvester further comprising a conveyor system, positioned between the front of the crop inlet of the bale chamber and the pickup assembly, further positioned below the supply inlet (203, 323) of the crop supply chamber (200, 320); wherein the conveyor system comprises a front roller, a rear roller, at least one conveyor belt, capable of endless rotation around the front and rear rollers; wherein the crop supply chamber (200, 320) further comprises a front wall (201, 321), a rear wall (202, 322), and a storage volume (210, 328); wherein the storage volume (210, 328) is defined by the space between the front wall (201, 321), the rear wall (202, 322), the pair of oppositely facing sidewalls, the control surface (204, 324) and the supply inlet (203, 323); and wherein the control surface (204, 324) is able to move to a higher position in between the front wall (201, 421, 521) and the real wall (202, 422, 522), thus increasing the size of the storage volume (210, 430, 528); and to a lower position in between the front wall (201, 421, 521) and the rear wall (202, 422, 522), thus decreasing the size of the storage volume (210, 430, 528).