Went out and hunted a few days last week, here's my observations.
Day One: Hunted Public land by myself and my dog within a 60 mile radius of Mitchell. Started hunting about 1:00 on a piece of land I did well on last year. Only saw 1 rooster and got him. 2-4:00 was a lot of driving and a little walking as a tried finding new ground. I just wasn't coming across much of what I like (corn, cattails, tree line, prairie, different types of grass, water all within a half mile or so of each other), just a lot of public land surrounded by cattle pastures and not much else. Found a new piece at 4:00 and got my final 2 roosters by 4:30. Lots of birds in this spot. Got back to the truck and sat on the tailgate with the dog until it got dark, just enjoying the sunset and hearing all the cackles around me.
Day Two: Hunted private land with a group of 5 and 2 dogs, about 20 miles from Platte. We got 12 and certainly had our chances for our 15. Most birds were shot out of walking tree lines and shelter belts, not a lot in the prairie. It was also very windy, so that may have made a difference.
Day Three: Hunted public land with a group of 7 and 4 dogs within a 90 mile radius of Mitchell. I never have high hopes on public with large groups. I think public birds are smart and when I hunt them myself I usually do okay but really make sure not to talk with my dog, slam car doors, or hit the lock button on my car's remote to sound the hound 2 times... Large groups in public is just too loud when you enter, too much talking while walking, too many people yelling at dogs. We got 4 for the day, and should have just split up into smaller groups so each group had a dog. In a large cattail area we saw one of the bigger bird flushes I've ever seen on public land about 200 yards ahead of us. Must have been about 300 birds that got up over 3 minute time span as we entered the area.
Day Four: I did not hunt this day, but a group of 7 got 17 on private land.
Overall: If you are a group of 1-2, maybe even 3, with a good dog, you can reasonably expect to get your limit of roosters on public land with a full days work and putting all your effort into it (meaning you are an individual that is in shape and has no problem walking 10am to sunset while high kneeing it through thick grass). If you drive slow and road hunt the final 90 minutes of the day, you could also see some birds. Overall bird numbers are fine. Sure you won't limit by noon, but you can still have a good time and enjoy your trip. Not many birds relating to cattails yet, but a fair amount in the grass next to them. Look for grass, tree lines, shelter belts, harvested corn, cattails, water, and you'll find birds somewhere in the area.
One other thing to note. Between 5 years of living in SD and 6 years of going back to hunt every year, I ran into the GFP for the first time ever. Started off as not a big deal, checking shells and licenses. Then started calling each member of our group into his truck one on one. Turns out 4 guys in our group unknowingly left public land for a tiny bit and they all got trespassing tickets. They walked inside the public land heading north and planned on heading west when they got to the boundary sign. The piece of public land wasn't a square section, and they knew it didn't go all the way to the road. As they got closer to the road, they realized something must be up because according to the map the public land should have ended by now, but they never saw a boundary sign or fence line or anything. They then turned around and heading back south a ways then west towards the parking lot. They got back to the parking lot with GFP waiting, and all got issued trespassing tickets and fines.
They did not knowingly trespass, and turned around once they started realizing the public land shouldn't be going this far north. There was no sign. GFP said there does not need to be signs and each hunter should have GPS on their phone and know the boundaries from that. Really wasn't a very pleasant situation. You got 4 guys who are trying to do the right thing who get tickets. You get who knows how many people who knowingly go onto private land to chase a bird who get nothing. One thing we asked was that the $500 the state made off of their fines that day, that the money goes directly towards signs or a fence on the north part of this public land. The GFP response, "I might bring it up to my supervisor." It also took him 2.5 hours to write the 4 tickets, who knows why it took so long.
Moral of the story, while we thought we were being safe and following rules, and studied the property in the public land book, we still violated the rules. And since we took the time to study the map, the guys knew the property didn't go all the way to the road which is why they turned around as they kept getting closer and closer to the road and still no boundary sign they could see.