I recommend an oven thermometer. I don’t think rack position makes a huge difference, but your oven temperature could be off by 50 or 75 degrees.
Tastes like… victory…
In the OP’s case, … chicken?
Another middle racker here, although it’s actually slightly lower than the exact center of the oven. I have noticed that food cooks faster but burns easier on the bottom rack, and it throws the recipes off so we never use that.
Congratulations – that IS the middle! The OP is asking about placement, not saying there are physically a top, middle, and bottom rack.
The bottom gets more radiant heat from the element. Good for pizza, bad for chicken.
In addition to fitting the tiurkey, the bottom can also be useful when baking 2 things on different racks. Better to have 2 ovens, of course.
I make angel food cake from a box mix (yes, I know making it from scratch tastes better), and the directions tell you to take out the top rack and put the remaining rack in the bottom position.
Otherwise, I use the middle rack.
Normally you want the food to be centered in the oven, which usually means having the rack a notch or two below the centre position, depending on the size of the thing you’re cooking.
The bottom position is for things you want to cook quickly at high temperature. I only use it for pizza.
rack positions are entirely dependant of what kind of oven you have. In my of, gas heated, oven, the hottest place was at the top and the coolest at the bottom. In my (fairly new) fan assisted oven I can choose whether to use just the fan, just a bottom or top heater or all of the above.
With the fan, which is the default setting for 90% of my cooking, it makes little difference. I tend to use the bottom shelf because then I can see what’s going on through the glass door. Pizza gets moved up a shelf so the bottom gets cooked faster.
This. Middle is default. Anyone who says otherwise is a wrongheaded poopyface. 
This struck me too. My oven runs about 25 degrees hot. The OP needs to just turn on the oven for 20 minutes and look at the thermometer.