I got 6 Golden Comets 2 years ago and they laid eggs faithfully until 6 months after getting them. They only laid eggs periodically after, I got new comets last year. Now the older hens are dying. They eat and drink water, they just keep get hunched up and stand around or the just lay down in different places. They seem like they are happy and want to hang with other chickens. A couple of chickens did this off and on for a month or so. Then we find them dying. 1 only did this for a day and then died. It's only the older hens. I think they are around 4-5 years old. I clean the coop every day and make sure water is clean and changed often. They get ACV and probiotics in the water, plus plain water. It did get really hot for a month though. These are my first chickens ever. I still get and egg from them about 1- 2 x a month. Is this just their old age???