No, you can not own a flamingo as a pet. ... Flamingos are protected under the Migratory Bird Act. They are wild animals and it is not legal to own a flamingo if you are not having a special license.
How rare is a flamingo in Adopt Me 2020?
The Flamingo is a limited ultra-rare pet, which was added to Adopt Me! on July 5, 2019. As it is now unavailable, it can only be obtained by trading or by hatching any remaining Safari Eggs. Players have a 15% chance of hatching an ultra-rare pet from the Safari Egg, but only a 7.5% chance of hatching a Flamingo.