Gathering Fertile Eggs

[Laingcroft]

Not sure if this the right place for this question but here it is --- how long does one wait after setting up a breeding pen before gathering eggs to make sure the cock bird in the pen is the actual sire? I've been gathering at 5 weeks, but it appears that isn't long enough since there was an oopsy in the last hatch that had to have come from the previous cock bird.

 

[Pyxis]

They say to wait at least a month, and after that chances are good they'll all be fathered by the new cock. Five weeks though, wow! Maybe she got out or something and mated with the other boy?