“Please send me a letter in response.”On Nov. 30, Marcia Mayeda, the director of the Los Angeles County Department of Animal Care and Control, wrote back.Unicorn owners must feed their unicorn watermelon, “one of its favorite treats,” once a week, she said, and polish the unicorn’s horn “at least once a month with a soft cloth.”In addition to the dietary and grooming requirements, the unicorn must have “regular access to sunlight, moonbeams and rainbows.”“Any sparkles or glitter used on the unicorn must be nontoxic and biodegradable to ensure the unicorn’s good health,” she said.Beyond the sparkles and moonbeams, the unicorn must also be cared for in compliance with Title 10 of the Los Angeles County Code, which governs animal control and health, she said.The Animal Care and Control Department also issued Madeline a heart-shaped unicorn license tag and gave her a stuffed unicorn to look after while she searches for a unicorn of her own, noting that the creatures “are indeed very rare to find.”The department shared the letter, the license and the stuffed unicorn on Instagram and Facebook on Tuesday, redacting Madeline’s last name from the posts.Ms. Mayeda declined to arrange an interview with Madeline or her family because she does not yet know that her license request has been approved; her mother thought the license would be a good birthday present later this month."