My 4 yo black australorp hsa had runny poop/diarrhea for weeks. Everyone else seems fine, and she looks and acts super healthy. I've had her poop tested for worms, but it cam back negative. There has been a lot of change in the flock with new pullets getting introduced and one of my others going broody and now raising 1 week olds. Could it just be stress? The fact that they are all eating grower feed? I've been giving electrolytes and probiotics and treated their water with vinegar, but no change. Any thoughts? I'll try and upload a picture of the poop soon...