I worked in a jail kitchen. My ex was a corrections lieutenant up for security manager, about 18 years ago.
We didn't use road kill in the jail, they use almost exclusively turkey products. It's cheap and any religion can eat turkey, it seems.
But I know for a fact that prisons have used road kill because I know the game commission guys who provided it to them. I don't know if they still do, probably not, though different states may have different regulations.
BTW, when I worked at the jail, we made the inmates' food...and about half the time we made the officers something else. Jail food is NOT good.
But we had to contract out to the prison down the road when we were resurfacing the floor of our kitchen, and their food was incredible.
My advice to anyone who plans to take up residence in prison: Declare yourself a vegan. You will get INCREDIBLE food. And believe me, you're not missing anything if you opt out of the meat.