It's unlikely to be "an illness in the coop". Or at least, not one you can scrub out of existence.
Reproductive issues are notoriously difficult to identify and deal with. Egg binding might be one of the easier ones to detect, though.
Behavior is pretty explicit. A hen having a problem getting an egg out will behave by slowing down to being a walking zombie. She walks in slow motion, dispenses with all the typical quick chicken body language, and will often spend time on the nest without producing anything.
Her butt feathers will often be wet from the fluids being diverted from the cecum, and it may have a bad odor. Her tail will often be held low and flat.
Instead of Tums, which is calcium carbonate and harder to digest and absorb, use this.
View attachment 3093519
One tablet directly into the beak, followed up each day with another as long as the crisis endures.