It is always best to go the quarantine route when bringing in new poultry.
New poults should be disease free already. Introducing poults to a hen can be very easy or very difficult depending on the hen.
What I do is to have poults in my grow out pen. Mine are two weeks old when I move them from the brooder to the grow out pen.
I then let a hen in with the poults. If the hen starts cooing at them and gathers them to her, I leave them together. If the hen starts pecking at them, I immediately remove her.
Some hens are really good about adopting poults, some are really bad.
Do not use the method used by some people who stick chicks under a broody hen at night. If you do that with a turkey, you are likely to find dead poults in the morning.