The ornamental design for a carton for a petfood supplement, as shown and described.
FIG. 1 is a perspective view of a first embodiment of a carton for a pet food supplement embodying a new design;
FIG. 2 is a front view of the carton for a pet food supplement thereof,
FIG. 3 is a top side thereof and is identical to a bottom side view thereof;
FIG. 4 is a left side view thereof and is identical to a right side view thereof;
FIG. 5 is a bottom view thereof; and,
FIG. 6 is a perspective view of a second embodiment of a carton for a pet food supplement embodying a new design, of which FIGS. 3-5 are identical for this second embodiment.
The surfaces with stippled shading and solid lines in FIGS. 1, 2 and 6 are the claimed design. The stippled surfaces thereof indicate a contrasted color within the carton for a pet food supplement. The broken lines in the drawings represent the boundaries of the claim and unclaimed environmental subject matter. The broken lines form no part of the claimed design.