This will slow down there breeding. I have always kept them together but I don't think it would hurt keeping them separate. Do you just have blue bars or do you have different colors?
Homing pigeons are amazing birds be aware that once they start breeding they are worse than rats, they multiply fast. I always built a chicken coop type area for them. usually put some small doors about 4 foot off the ground for them to go in and out when you want them to. If you get them young...