First lets use Colorado as an example....
Colorado is home to two subspecies of wild turkey: the Merriam’s wild turkey (Meleagris gallopavo merriami), which occupy
the mountainous regions of Colorado and the pinyon-juniper canyon/mesa country of southeastern Colorado, and the
Rio Grande wild turkey (Meleagris gallopavo intermedia), found primarily in the cottonwood riparian systems of the eastern
plains region, in addition to the Rio Grande River area in the San Luis Valley of south-central Colorado.
I use Colorado as an example as the Merriams subspecies was native and the Rio Grandes were introduced into eastern Colorado creek bottom areas in the 80's. Probably more unlikely they intermixed with Merriams, purely from a logistical reason...distance. Here's a photo I clipped of a Colorado Merriam's. Disclaimer....do not know where photo was taken, but was labeled as described. See the similarity to our northeastern birds? All subspecies have variances, due to any number of factors, just like all wildlife.
Now lets look at a couple Merriam's from New Mexico.............
Another..... high-country New Mexico Merriam's turkey. This bird was taken on the edge of a beautiful canyon in the Gila National Forest. (2010)

Subspecies inhabit areas based on habitat preference. Rio's just generally like more open country, Merriam's prefer forests with an open understory, and Easterns, who spend the majority of their time inside the woodline as part of their scientific name suggests...
silvestris. It was named by L.J.P. Vieillot in 1817 using the word silvestris, meaning “forest” turkey.
Did we have some mixing of subspecies? Yes where they overlapped in the NE, but for the most part, Rio's will be Rio's and Merriam's will be Merriam's in choice of area to take up residence.