The Egg's Parent is Kagechiyo? (たまごの親は影千代？の巻 Tama go no oya wa kagechiyo? No maki) is episode 65 of the Ninja Hattori-kun 1981 anime.
Kenichi learns about how chickens hatch eggs in school and attempts to hatch one himself back at home. Shinzō and the others ask Kenichi about it and he replies that if the egg hatches, they can have as much fried egg as they want next time. They put a thick blanket over Kenichi's egg and beg Mrs Mitsuba not to take it.
After a long time, they started to get confused about why the egg still had not hatched. Doing a bit of research, Hattori found out that eggs from supermarkets will not hatch and are only meant for eating. The gang went to a farm and took an egg back. A duck was seemingly angry at what they did. Kagechiyo spotted the egg and wanted to eat it, following them back to the house.
Kagechiyo went into Kenichi's room but Hattori hypnotised him. Kagechiyo, thinking he was a Hen, sat on the egg. The egg successfully hatched. To everyone's surprise, it was a duckling that hatched! The duckling imprinted on Kagechiyo, thinking he was their mother. The episode ends with Kagechiyo denying it loudly and Hattori saying "The plan had worked, but they were the wrong eggs!".