I have a hen hatched clutch of chicks, origially 5, that are two weeks old and have been having babies slowly die. They are (well had been until two days ago) been free ranging and I have the first two die off within the first week. One without me seeing and the other acting like it couldn't see and subsequently dying over night. I have moved the hen and the remaining three to a isolation/nursey area and now have another chick that started acting listless yesterday and now is acting neurologic. Head tilted to the side and unable to stand up straight. I have written this one off as lost, but wanted to know if anyone had any ideas. The other two are strong and seem to be growing and thriving like normal. The hen is a 3 year-old, full blood white leghorn so originally I thought she was just not a great mother since it is rare for them to go broody, but with them being confined and still having issues I am thinking it may be something else. Mareks maybe? I have roughly 35 and no one else is sick...