The ornamental design for pet feed, as shown and described.
FIG. 1 is a top plan view of the pet feed of this Design;
FIG. 2 is a front view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a back view thereof;
FIG. 5 is a right side view thereof; and,
FIG. 6 is a left side view thereof.
