If they were Missouri Dept of Conservation agents, which is the primary state agency that would be doing what you describe, you can find them on the VHF conventional repeaters. Sometimes they will use the local County Sheriff dispatch channel to run subjects and some even will use MOSWIN to run subjects through the Troop A Dispatcher on 20007. I do not hear subjects run very often on their own radio system but have heard them numerous times on MOSWIN and the local county they happen to be operating in. They ID themselves as CONSERVATION 6## when on MOSWIN or another agencies channel.
I do not think DNR does this type of stuff outside of the State Park Boundaries. But they can often be heard on MOSWIN as RANGER ##. Not sure if they still have a VHF system in place or not.
The MDC rangers for the KC Region, which includes Henry/Benton use 151.400 (D503). Most of this is car/car. They also use the cell phone a lot due to poor coverage on the repeaters in a lot of areas. Repeaters are capable of analog encryption and they use it sometimes but not often.
Gregg in KC