RIR, yeah I would expect some better. These things are often solved with patience, don't be surprised if you see a real increase really soon. But I'll go through some things.
Do you know how many different birds are laying? Is it a case of not many laying or of them laying irregularly? What are you feeding them? What percent protein? Do you provide most of what they eat or do they forage a lot?
Do most of them have bright red combs and wattles or do many of them still have pale combs and wattles? One way to help determine which are not laying is to look at the vents. A tight dry vent means that pullet is not laying. A soft moist vent means she is laying or is getting ready to. When you look it is easy to tell the difference.
Is it possible they are hiding a nest? That's a fairly common reason people think they are not laying.
Is something getting the eggs? Most critters, including the chickens, tend to leave signs like egg shells or a soggy mess when they eat eggs. It's possible the chickens could clean up the shells after some other critter, but they are usually not that good at cleaning up all of them. If it is a lot of eggs it is even less likely they will clean all of the shells up.
The critters that typically leave no signs are snakes, canines, and humans. It's probably too cold in Nebraska for snakes to be that active. The way a snake eats is to take a few eggs (how many depends on size) and go away for a few days to digest them, then come back for more. From what I've seen, four eggs at a time is about right for a 5' long rat snake. I doubt it is a snake in Nebraska this time of year but maybe you can see a pattern?
Canines can eat eggs whole but if it were a fox or coyote I'd expect you to be missing some chickens, not just eggs. Dogs however will often learn to leave chickens alone but eat eggs. How possible is this? It doesn't have to be your dog.
I'll let you decide if a human is possible.
I still think you need to be a bit more patient, spring is coming. It should not be long before you are buried in eggs. But maybe this gives you something to think about.