Other's Day (book 5 of the Willy series)

Book 5 of the willy series. Will overheard Otis, the farmer's son talking to a friend about Other's Day. Willy had no idea what Other's Day was, but it sounded important. It was the day that you showed your love. So Willy set about figuring something out for all his friends.
He found all kinds of things, but he had trouble finding anything for Mother Hen. He loved Mother Hen most of all, so he had to find something for her, but what?