I do not let them be out of cage unsupervised. The hens cage has been opened a few times but she never leaves the cage so I stopped doing it.
And thank you all for your information, it helps alot. It's not my first time breeding, this has just never happened before.
But he will not be bred anymore and will not return to her cage, in case they get in the breeding mood again.
So thank you. It helps alot.