I had a prior post on this, but one of my 3 oldest hens is becoming more delayed in her speed and reaction compared to the rest of the flock. She is a red sex link and will be 4 in November or December. She seems to drink normally, she does nibble at food, as well as looking healthy. Overall no visual issues at first inspection, but her crop feels harder and tighter compared to the other hens. She has had crop issues in the past, but I’m not sure if she has the same issues. She was just recently huddled close to the run with both eyes completely closed. The rest of the flock is healthy. What should I do?