Hi, my sister has a pair of Tumbler Roller Pigeons. She keeps them in a small run outdoors with a nest box for them to perch in at night. We got them at a poultry show 3 months ago and they are doing quite well. Despite this, I have no idea whether they are male or female. I would like to know; do to that my sister wishes the 'pair' to raise squab. Since my sister isn't very knowledgeable about poultry and is just starting out in 4-H I'm determined to find out for her... I figured that you all could help 
Here's what I do know... one of the birds is female do to the fact that infertile eggs are laid in the nest box (or they just never developed). Based on this, is there a male too? Or are they like chickens, males don't need to be present for eggs to be laid? If there is one male and one female then how do I know which is which? Any help would be appreciated!

Here's what I do know... one of the birds is female do to the fact that infertile eggs are laid in the nest box (or they just never developed). Based on this, is there a male too? Or are they like chickens, males don't need to be present for eggs to be laid? If there is one male and one female then how do I know which is which? Any help would be appreciated!