A feeder assembly characterized in that it comprises: a tray member (104); an outer grill member (184) that is operatively associated with said tray member, said outer grill member defining a plurality of openings therethrough through which the birds can eat the feed provided in said tray member; and a first and second inner grill members (408, 408 ') which are generally positioned within said outer grill member (184), said first inner grill member (408) being configured to move relative to said outer grill member (184) in a first direction to cover portions of a first set of said openings through said outer grill member (184) to effectively change said width of said first set of said openings through said grill member, said second inner grill member (408 ') being configured to be able to move relative to said outer grill member (184) in a second opposite direction to cover portions of a second set of openings through said member of outer grill to effectively change said width of said second set of said openings through said grill member.Un conjunto alimentador caracterizado porque comprende: un miembro (104) de bandeja; un miembro (184) de parrilla exterior que está asociado operativamente con dicho miembro de bandeja, definiendo dicho miembro de parrilla exterior una pluralidad de aberturas a través del mismo a través de las cuales las aves pueden comer el pienso proporcionado en dicho miembro de bandeja; y un primer y segundo miembros (408, 408') de parrilla interiores que están, generalmente, posicionados dentro de dicho miembro (184) de parrilla exterior, estando dicho primer miembro (408) de parrilla interior configurado para poder desplazarse con respecto a dicho miembro (184) de parrilla exterior en una primera dirección para cubrir porciones de un primer conjunto de dichas aberturas a través de dicho miembro (184) de parrilla exterior para cambiar de manera eficaz dicha anchura de dicho primer conjunto de dichas aberturas a través de dicho miembro de parril