The ornamental design for a walk-in pet bath, as shown and described.
FIG. 1 is a front perspective view of a walk-in pet bath, showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a front perspective view similar to FIG. 1 showing the walk-in pet bath in operation with a dog and a hose connection for supplying water to bathe the dog.
The broken lines showing in FIG. 8 are for purposes of illustrating environmental subject matter and form no part of the claimed design.