An ornamentaldesign for a hair display piece, as shown and described.
FIG. 1 is a perspective view of the hair display piece with the mounting thereof being shown in dotted lines, the same not forming a part of the design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a side elevational view as seen from the right hand side of FIG. 1; and,
FIG. 4 is a side elevational view as seen from the left hand side of FIG. 1.