I had mookie pigeons for a few years, then when I was away no one took care of them and I came back to find my best of show black mookies dead. I like the jacobins and the volgas also, but the mookies were just so funny, they always seemed nervous. What kind of fantails do you have? I like the Indian fantails because they look more elegant.
The best way to know is if you see one strutting and cooing, it is a boy. Only male pigeons coo. About your fantails, are they big and do they have feathered feet or are they small with their head on their backs? The Indian fantails are big, long, have feathered feet. The American fantails are small with their heads thrown back.