I went to let Jack and the 9 girls out of their house this morning and 3 of the hens were dead. 2 fell off thier roosts and one in a box. All were close to a window. They are 5 months old. Some are laying. No predator got into the house. One hen died a month ago, the day after she laid her first egg. What could have happened to them? These are my first chickens and I'm pretty attached to them. They didn't get into any poison, as far as I know. Nobody looked distressed last night at bedtime. Adding on... They have a very nice coop. Off the ground, fenced yard, access to fresh water and food all the time. Their coop is in the shade and has a temperature acctivated fan. They free range all day. This happened between 7pm and 8am. They were stiff and dusty. It does not appear that they died traumaticly. They appear to have just fallen off the roosts backwards. They were lying flat on their backs, legs stretched out, eyes closed. One went before the other because ones legs were on the others head. The one in the box had her head dangling and the legs stretched out behind her. Also, there was 2 rubber eggs on the floor. They had been broken and trampled.