Hey friend! Oldhenlikesdogs is another wonderful helper im sure shes steering you right. To sit tight and be aware. Probly a partial molt but good husbandry is watching closely and asking questions.
If you wanted to do some extra recon work u might wipe the roosts and nest boxes with a clean white paper towel to check for mites. There would be blood smears afterward but as no one else is affected i doubt you have parasites.
The other thing that would come up is egg peritonitis when it seems a hen suddenly isnt thriving and isnt laying. The eggs arent formed all the way for one reason or another(usually calcium deficiency which shouldnt happen with your layer feed) and the unlaid yolks can poison the poor critter.
If you wanted to do some extra recon work u might wipe the roosts and nest boxes with a clean white paper towel to check for mites. There would be blood smears afterward but as no one else is affected i doubt you have parasites.
The other thing that would come up is egg peritonitis when it seems a hen suddenly isnt thriving and isnt laying. The eggs arent formed all the way for one reason or another(usually calcium deficiency which shouldnt happen with your layer feed) and the unlaid yolks can poison the poor critter.