Animal Pen

FIG. 1 is an upper front perspective view of an animal pen, illustrating our ornamental design;

FIG. 2 is a lower rear perspective view thereof;

FIG. 3 is a first side view thereof;

FIG. 4 is a front elevation view thereof;

FIG. 5 is a second side view thereof;

FIG. 6 is a rear elevation view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines in the figures illustrate portions of the animal pen that form no part of the claimed design.