Question from The Dizzy Hen

[The Dizzy Hen]

My daughter has raised 6 hens that are 2 years old now. They have only laid 2 weeks since they were old enough to lay. Now, she has lost 4 of them in one week. She’s taken very good care of them, but is at a loss as to what has been going on. Now, one of her 2 remaining is just standing in the same place constantly. She never moves. I’ve raised chickens for years, but I have never known of anything like this before. She keeps the coop clean, feeds and waters well. She lives in Missouri if that helps.