The scenario about the hen being used for food when it becomes too old to lay is invalid.
Murder is murder.
Similarly, the calf who is weaned by hand, and who shares its mother's milk is not treated as a veal calf. Supposedly the cows feed does not contain the atrocious additives modern beef cattle ingest. In a natural situation, ie when a calf is weaned, mother's milk dries up. There would be no milk left for anyone to drink. Again, murder is murder.