Poultry-rearing system, having a plurality of upright supports that are arranged in a regular grid and set at a distance from one another and each of which incorporates an inserted end and a socket end and incorporates a first section having a first outer diameter referred to as outside diameter and in the area of its inserted end a second outer diameter that is smaller than the outside diameter and is referred to as inserted diameter, such that in the area of transition from the outside diameter to the inserted diameter a shoulder extends all the way round, where a support is constructed in the form of a tube and incorporates as a single-piece component part the first section and the area of the inserted end connected above to the shoulder, where at each support point at least two supports are arranged one above the other and the supports incorporate shoulders each of which extends in a radial direction, and having a plurality of longitudinal members and cross-members attached to the supports, where a number of longitudinal members and cross-members are each arranged on one level of the poultry-rearing system and the poultry-rearing system incorporates at least two levels arranged one above the other and the longitudinal members and cross-members are each constructed in the form of angled profile bars, the cross-section of each of which incorporates an upright section and a horizontal outer section and in the horizontal outer section a recess referred to as a drilled hole (14, 15) is arranged that incorporates a diameter that is smaller than the diameter of the shoulder, characterised in that a longitudinal member and/or a cross-member is constructed in the form of a U-profile formed from metal sheet the cross-section of which incorporates an upright section forming a middle section and two horizontal outside sections extending one above the other a distance apart, where in the two opposing outside sections two recesses referred to as drilled holes (14, 15) are arranged one in line with the other, of which at least one drilled hole incorporates a diameter that is smaller than the diameter of the shoulder, and of the two drilled holes (14, 15) in a longitudinal member or a cross-member a first drilled hole incorporates a first diameter that is larger than the inserted diameter and smaller than the outside diameter of a support and the second drilled hole incorporates a second diameter that is larger than the outside diameter of a support. having a plurality of upright supports that are arranged in a regular grid and set at a distance from one another and each of which incorporates an inserted end and a socket end and incorporates a first section having a first outer diameter referred to as outside diameter and in the area of its inserted end a second outer diameter that is smaller than the outside diameter and is referred to as inserted diameter, such that in the area of transition from the outside diameter to the inserted diameter a shoulder extends all the way round, where a support is constructed in the form of a tube and incorporates as a single-piece component part the first section and the area of the inserted end connected above to the shoulder, where at each support point at least two supports are arranged one above the other and the supports incorporate shoulders each of which extends in a radial direction, and having a plurality of longitudinal members and cross-members attached to the supports, where a number of longitudinal members and cross-members are each arranged on one level of the poultry-rearing system and the poultry-rearing system incorporates at least two levels arranged one above the other and the longitudinal members and cross-members are each constructed in the form of angled profile bars, the cross-section of each of which incorporates an upright section and a horizontal outer section and in the horizontal outer section a recess referred to as a drilled hole (14, 15) is arranged that incorporates a diameter that is smaller than the diameter of the shoulder, characterised in that a longitudinal member and/or a cross-member is constructed in the form of a U-profile formed from metal sheet the cross-section of which incorporates an upright section forming a middle section and two horizontal outside sections extending one above the other a distance apart, where in the two opposing outside sections two recesses referred to as drilled holes (14, 15) are arranged one in line with the other, of which at least one drilled hole incorporates a diameter that is smaller than the diameter of the shoulder, and of the two drilled holes (14, 15) in a longitudinal member or a cross-member a first drilled hole incorporates a first diameter that is larger than the inserted diameter and smaller than the outside diameter of a support and the second drilled hole incorporates a second diameter that is larger than the outside diameter of a support.