How young is she? My Royal Palm turkey who hatched this time last year did an awesome job of sitting and hatching this year and is a wonderful mother as well. Her 14 poults hatched a year to the day after she herself hatched last year. My Bourbon Red hen who hatched in July last year is even younger, and she also sat very nicely and is raising 5 poults that are a few days old now, doing a marvelous job with them.
There is no way to tell when your hen will go broody but I wouldn't worry about her not doing a good job if/when she does.
I have had a chicken raise poults but I wouldn't recommend putting the eggs under your broody chicken. Chickens don't always recognize poults as babies and will instead attack them as though they are aliens. They look a little different and they sound VERY different, and the chicken isn't "programmed" to recognize that sound as belonging to her - therefore, it must be an intruder that needs to be sent packing.
The poults my hen raised last year, hatched in my incubator. The hen's 3 chicks hatched the same day so once the poults were dry, I carried them down and showed them to the hen. She recoiled in horror at first, but I set the poult down in front of her and after a few minutes she relented, and started clucking, and invited it under her wing. However that was an extremely maternal hen who had also raised ducklings for me - not all hens will do that.
This year I had the BR hen sitting on a nest on the floor of the coop and a chicken hen co-brooded with her. When the first poult hatched, it was attacked by the chicken and though I found it alive, it did not survive its injuries. Fortunately I was then able to move her with the remaining eggs and when they hatched under the turkey alone, the rest have done fine.
So if I were you, I'd continue to collect your clutch until your turkey does go broody (and she probably will at some point). If you are worried about the eggs getting old, you can always start them in your incubator and then if she goes broody while they are incubating, move them under her. That is what I did with my RP hen. I had eggs that were already a week into incubation when she went broody. I moved them under her so she only had to sit for 3 weeks instead of 4, but she did such a great job that all 14 of the eggs I gave her hatched.
