The ornamental design for a feeder especially for calves, as shown and described.
FIG. 1 is a left side view of a feeder especially for calves in accordance with our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a back view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a front perspective view thereof; and,
FIG. 7 is a back perspective view thereof.
The broken line elements shown illustratively in the last two figures depict exemplary components which might be used in conjunction with the feeder and do not actually form part of the design claim.