New hen

[bvill01]

Picked up a new hen but she was with another rooster how long do wait for her to be fertile from my rooster ?

 

[Ol Grey Mare]

Hens have been observed to lay fertile eggs up to and beyond a month beyond the last exposure to a rooster -- to be absolutely safe, I would allow at least 6 weeks before assuming eggs she lays are fertilized by your rooster.