Okay, so cutting the primaries only, as opposed to ALL the feathers, throws off their balance. However hard they "pump", they are getting an imbalance of "thrust : lift" ratio, and will nowhere. But if you cut ALL the feathers on a wing, then they are back to being in balance, and just need to "pump" harder to achieve some amount of flight. Is that right?See following link but modify.
https://www.backyardchickens.com/a/how-to-clip-trim-the-wings-of-your-chicken-to-prevent-flight
Cut the all the primaries so they extend no more than an inch beyond flesh of wing. Example in thread above is not cut quit tight enough. Feel around a lot to become familiar with all the feathers of the wings and how they are actually connected to the living tissue. You want to be comfortable as you give such a close cut. Make certain scissors are heavy enough for job. Many people cut too far out because scissors are too light. This time of year some birds will be in process of molting wing feathers which will cause two complications. First, feathers in blood will bleed but I do not think the birds can feel and second, cut feathers may soon be replaced with uncut versions.