I have a similar question about adding a couple of turkeys to our flock of 40 chickens next year. We have 20 acres and they are free range dawn to dusk. I'd like to raise 2-3 turkeys next year but don't have the means to add separate housing. We have wild turkeys from time to time but not large groups.
We have a neighbor with an incubator. Where would we get heritage breed turkey eggs?

Here is a good site to see all kinds of heritage turkeys. They sell eggs too. http://www.porterturkeys.com/index.htm

This site is about incubating turkey eggs. I incubated holland white eggs this spring with the info from this site: http://www.wikihow.com/Hatch-Turkey-Eggs-in-an-Incubator

You can free range turkeys, but you need to watch the hens close when they are laying. They will slip off and make a nest in the field. I had a turkey hen and her nest of eggs run over during haying. She stayed on the nest to protect them. No one saw her until it was too late.
I would reccomend keeping hens penned during their laying season.
The turkey hens seem to get along with chickens. They will chase the chickens off of the food. My tom killed one of my chicken hens trying to breed her. He got ahold of her neck and was twisting it while he was on top of her and broke her neck. I had a bourbon red tom that never bothered my chickens. So, it just depends on the tom.
Hope this helps!