unknown baby hen predator

It only a month since I got these two baby hens and I became very fond of these two especially the small brown coloured one so it was quite emotional and this afternoon I went to close them in the coop for the night but found only the white one slightly bigger than the other which came flying hidden from above a tree which is quite unsual because they always waited for me crouched just beside the coop. Then I looked around a bit trying to find the other one in the evening dusk with the help of a torch light and found a well known farel cat behind the coop but couldn't find the dead baby hen. Today has been raining and tomorrow same so I'll have to continue searching for it on friday.

I usually open the coop at six in the morning and close at six in the evening everyday. Is it too much?

Now I will have to keep my only baby hen left inside the coop and never let her outside until at least next summer when she will be grown up and able to escape these predator attacks.

Now the only thing left to happen is that an ill-intentioned person opens coop and steals my only hen left because if this happens it would be really bad.

Now this hen is alone in the coop it's cold and heavy rain and thunder outside & quite scary for her to live alone and together with this predator no one knows who this is. Just 2 or 3 days ago I saw a fox nearby but I doubt it would came in my home near the coop so I'm oriented on the neighbour's cat/dog or ill-intentioned person suspicion.

P.S. I think killing foxes with your rifle just because you lost three hens is quite borderline.

You do get to really like certain birds. Unfortunately chickens are easy game for many predators, no matter how large they are. If your hen is outside and unprotected, she us unlikely to survive for long. I would not assume the cat was the predator, either.

Like you I do not really agree with killing predators at random so that hens can free-range. Mainly because it is ineffective, as new predators are always coming along. And personally I like living with wild creatures around. Build yourself a good, predator-proof pen for your hen to stay in when you are not around to protect her, and get her a friend to keep her company.

And welcome to BYC

Hi! I'm so sorry this happened! Unfortunately, you now have a predator, so any time in an unprotected area would be too much. Whether a fox or dog or cat, it will be back. Chickens are quite social. could you possibly locate 2 or more youngsters to put with her? Is there a way you could bring her into the house for now? Chickens can be quite resilient, but she sounds very young.
I'm not sure about your climate, the breed or exact age of your baby, but a lone hen in a cold climate would surely not be best practice.
Possibly you could check craigs list or here in https://www.backyardchickens.com/newsearch?search=in+need+of+rehoming to find your baby a couple friends! Best of luck to you!

I encourage you to also post in New Member Introductions so folks can give you a proper welcome!
https://www.backyardchickens.com/newsearch?search=new+member+introductions