when the birds pair up and one lays eggs then you will know. that is the only 100% way to know, if you get 4 eggs you have two hens mated up, if no eggs you may have two cock birds. if you get two eggs and candle them and they are fertile you have a pair. if the eggs are not fertile and you only get two eggs then the cock is not filling the eggs for some reason, in that case you may have to trim some feathers from the vent area and thin the tail out, so they can mate better and fertilize eggs.