Erm....WRONG!! ;D ;D They'll interbreed.... and breed.... and breed.... and breed given chance!! ;D ;D
You'll have to watch for them laying eggs and them replace the eggs with pot eggs. They sit on the pot eggs till they realise they're not going to hatch, come off them for a few days then lay again!
I started with garden fantails in a dovecote - they make great pets - very easy to tame, don't wander too far, quite independent - just leave clean water out and throw out seed once a day. You don't need to remember to close them in at night and they don't need cleaning out more than a few times a year!! On the other hand, although they do fly around the house, you won't get the displays you would from a roller or tumbler!