One of my 4 RRR hens, Tarragon, has gone off the deep end. She no longer hangs with the flock but instead sits in the nest box 24/7. Whether there is an egg or not. Ive started taking her out in the eve as she doesnt even sleep with the flock on the perch anymore. I put her down, she drinks a bunch of water, pecks at some crumbles then walks around clucking softly then goes straight back the the nest. Is this normal? It seems very very odd that she's never with the flock anymore. Not grazing around the lawn or digging around for bugs or dust bathing. What do I do? Im really worried, Thanks for your help Rene'