I have a flock of 16 new hatchery birds that have grown out beautifully over the last seven weeks. 4 days ago a RIR started with 1 drooping wing. Then a drooping wing and a limp. Then drooping wing and a dragging non extended foot. Finally a drooping wing, and an inability to to open either foot on her own, so she could not walk. Before we noticed her lack of mobility, she was badly savaged by her flock mates. We isolated her and she continued to take water and feed, but would only sit on her rolled up feet and refuse to move. I euthanized her today, as i could not bear to hear her peep for her flock mates and she was so weak she could no longer stand, even when startled or open her feet. My concern now is for the health of the rest of the flock. None of them have demonstrated any of these symptoms yet, but I'd like to know if there are any preemptive measures I can take. This flock was on vitamin/electrolyte enhanced water for their first four weeks. They are on all organic chick grower with chick grit provided now.