One pair now has 2 healthy and fast growing squabs. Kind of 'cute' yellow fuzzy things that look like some weird prehistoric monster.
The other pair failed completely. The first egg was a good strong egg and was being brooded for a week before they managed to somehow crack it! The second egg had a weird shell.. dry and thin. And it was laid on the floor out of the nest. They also broke that before I discovered it.
I am hoping on of the squabs from the good pair will be female. Then I can pair it to the good male. The old female which keeps having egg problems will be retired for a few months. Maybe in the future I will see if she can be used to foster some other squabs.