Mating Nuc being robbed

[RHBee]

I had a swarm the other day and the parent hive had three queen cells. I decided to create a mating nuc for one of the queens. I noticed it was being robbed so I put a robbing screen in place. How long do I need to keep it in place to stop the robbing?

[VolunteerK9]

I keep screens on my nucs all the time. Robbing may have subsided for the time being but could start up all over again, setting your bees even further behind. I put them on and leave them on.