Feeding trough for poultry farming with automatic dispensing of the feed from a vertically displaceable horizontal dispensing tube (T), formed by just three pieces (1, 2, 3). The plate (3) is formed in one piece with a ring (9) which in the lowered position of the bell-like housing (1) opens a crown of apertures (12) and in the raised position of the bell-like housing (1) closes the crown of apertures (12) so as to reduce the amount of feed transferred to the plate (3). The feed trough is also configured to facilitate periodic rinsing thereof by providing a dome (7) formed in one piece with the plate (3), which plate (3) is rotatable relative to the bell-like housing (1), said dome (7) extending within the bell-like housing (1) so as to define therewith an annular chamber (8) for the passage of a liquid under pressure introduced into said annular chamber (8) through an inlet hole (11) of the bell-like housing (1), and a plurality of substantially helical projections (10) formed on the dome (7).
