1. aid device for unloading poultry cages, comprising an inflatable bag (9) provided with a connecting element (10) connectable to a supply of pressurized gas, said inflatable bag being (9 ) configured such that in a contracted state can be inserted into an interior space of a cage (50) and can then be inflated within said cage (50) by pressurized gas introduced through said connecting element (10) to an expanded state that restricts said interior space of the cage (50) at a reduced discharge located adjacent a door (7a) of the cage (50) sized to allow passage of a bird corral.2 space. Device according to claim 1, wherein said connecting element (10) is further connectable to a device succión.3. Device according to claim 1, wherein the inflatable bag (9) is provided with a second connecting element (12) connectable to a device succión.4. Device according to claim 1, 2 or 3, wherein the inflatable bag (9) in a contracted state is dimensioned to pass through said first gate (7a) or a second port (7b) located at one end of the cage (50) opposite the first gate (7a) 0.5. Device according to claim 1, 2 or 3, wherein the inflatable bag (9) in said expanded state substantially in the form of a parallelepiped conjugated form the interior of the cage (50) and having a truncated apex (9a ) providing said reduced adjacent to the door (7a) provided for the discharge of the cage (50) 6 discharge space. Device according to claim 5, characterized in that said truncated apex (9a) is configured to provide reduced adjacent to the door (7a) located at or near a longitudinal end of a front wall (2) of the cage discharge space (50 ) .7. Device according to any one of the preceding claims, characterized in that the airbag (9) is dimensioned so that when it is inside the cage (50) in the contracted state allows full freedom of movement to a number of poultry in space inside the cage (50), and in the expanded state restricts the freedom of movement the same number of poultry in the reduced
