A feeder comprising an elongate receptacle for food a removable part and an elongate restraining pin positioned within the feeder. The direction of elongation of the elongate restraining pin is parallel to that of the feeder. When in an engaged position, the elongate restraining pin is engaged with the removable part so as to couple the removable part to the feeder, and, in a retracted position, is disengaged with the removable part as to uncouple the removable part from the feeder.
