Abstract: The elevated upper floor 11 of a poultry fattening enclosure comprises a plurality of adjacent endless belts 15a, 15b, etc. movable in unison toward a transverse cross-conveyor 17 at one end of the enclosure to facilitate the removal of the birds. Each belt comprises a plurality of I-shaped double bushings 29 journalled at their ends to cross rods 30 to form a flexible floor grate, which engages sprocket-like rollers 20 at both ends of the run. The lower belt runs may comprise only drive cables 38 to save material and enable the free dropping of excrement to the lower enclosure floor 10. Alternatively, the floor 11 may comprise a series of rectangular frames 41 in which grates or mats 42 are clamped, the frames being connected by withdrawal cables 43 which pull them through slots 47 in an end wall 48 of the enclosure.