Sound like crested ducks. That is not a breed but a trade they can have. Just make sure that they don't breed each other, or another crested duck. It's a deadly defective gene that causes the crest. You end up with tons of dead ducklings if you try to breed one with another one. They are also known for neurological issues like seizures. Pretty looking, but not good to breed at all. If you breed them then you have to breed a crested with a non crested and end up with about half of them having a crest.