I have a rather large flock of 66 and all free range. 12 of my flock are very wild so to speak, they have no contact with myself or my husband other than running past us when we open the hen house door in the morning and the run door and off to the woods they go. We do not get the opportunity to observe them as we do the rest of our flock. Their hatch date is April 13 and I purchased this group from a local feed store that I have purchased from previous. We have a pullet that is limping, lethargic and seems to be gasping for air. This morning before I opened the run door to let everyone out I caught her with a net. She was running but you can tell she is sick. I have her quarantined in a small dog kennel in my mud room. None of my flock are vaccinated as we only use our birds for egg production and of course my pets. I have never lost any of my flock to illness. Any suggestions on what to do or what this could be. These chickens are my babies and a huge part of my life. Please help.