The ornamental design for a head for a toy, as shown and described.
FIG. 1 is a front perspective view of a head for a toy in accordance with the present invention;
FIG. 2 is front elevation view of the head for the toy shown in FIG. 1;
FIG. 3 is rear elevation view of the head for the toy shown in FIG. 1;
FIG. 4 is a right side elevation view of the head for the toy shown in FIG. 1;
FIG. 5 is a left side elevation view of the head for the toy shown in FIG. 1;
FIG. 6 is a top plan view of the head for the toy shown in FIG. 1;
FIG. 7 is a bottom plan view of the head for the toy shown in FIG. 1; and,
FIG. 8 is the front perspective view of the head for the toy shown in FIG. 1 shown in combination with a body for a toy in broken lines, the broken lines depicting environmental subject matter that forms no part of the claimed design.