A semen stock for artificially inseminating poultry, comprising a single shot dose of semen, an open ended flexible tube having a hollow cylindrical portion in which said dose is maintained by capillarity and presenting an inner diameter substantially greater than its wall thickness, and a reentrant brim at an open end of and integral with said cylindrical portion, whereby said brim presents in axial succession an inner free edge in direct contact with the inside of said cylindrical portion of the tube, and first and second portions which respectively converge and diverge in a continuous concavo-convex shape.