Everything east of highway 144 as it crosses the South Platte along I-76 is by draw, both public and private. West of 144 is OTC but largely private. There are some public tracts along the South Platte that are pretty good - I've seen a lot of birds at Centennial SWA and there is another just east of Greeley. Those will be Rios or hybrids.
You will find a lot of public land in the mountains along the front range, those are gonna be Merriams.