I really don't think it is an issue, as healthy adult pigeons can and do raise 2 healthy babies in a clutch, if the parents have access 24/7 to plenty of variety of food and a good breeding mix in their nest box. I think if you have foster parents to foster the one baby and the parents the other, that is okay.
However, all parent birds and foster parents should be innoculated in advance and treated with prevention measures, prior to their breeding, as specified in my link on your other thread. They need to be of optimal health.
However, all parent birds and foster parents should be innoculated in advance and treated with prevention measures, prior to their breeding, as specified in my link on your other thread. They need to be of optimal health.