I am so sorry. It is very normal to be sad when you care about this hens. I understand. A couple of weeks ago my husband went our and found one of our Buffs laying lifeless. She has been pecked to the point that we thought she lost her eye and was dead. My husband brought her in the house and we have been nursing her back to health. Every time we try to reintroduce her, the other hens start to peck at her again.
So now we have a another problem, she is so use to us and being spoiled, that she thinks she is one of us and not a chicken. So I worry that she will never be accepted back into the flock (if she ever was).
Again, I am really sorry for your loss. It is hard to lose them. I lost a couple of serama chicks last month. They were a week old. One morning they just died, still not sure what I did wrong. I cried like a baby when I lost them.
Just know you are not alone. We all get attached to this little critters. But remember, they are still animals that are a part of a natural system that you do not control. Things happen. All you can do it love them and treat them with respect.