Greetings
Yus745,
If your chickens are young and all the same age, then, this could be considered abnormal behavior.
Many times a chicken will be listless for a few days, due to a mild infection, and then recover on their own.
However, it is good for the keeper to be proactive. Do an exam on your hen. Wrap her in a towel so she doesn't get stressed.
- Check her crop this evening, take note of how full it is and if it is firm or soft. First thing in the morning check the crop again, it should be empty and flat. Also, smell her mouth for any foul odors.
- Next, feel her belly between the legs. Is it swollen like a balloon filled with water?
- Then, check under her feet. Do you see any cuts, cracks, sores, or scabs? Are her leg scales smooth?
- Look through her feathers, any skittering mites on the body, or egg clusters near the vent?
- You didn't mention her poop. Hopefully, it is firm with a white cap. Look for any sign of tapeworm (little white beads on the poop, that start to move). A fecal float test at the vet is best for detecting other parasites.
- Her eyes should be round and clear, nostrils dry. Put your ear up to her chest, hear any rattling or gurgling?
- Feel under the wings, any lumps or sores?
If all these things look OK, then just keep an eye on her. Make sure she continues to eat and drink well. If she starts showing concerning symptoms, just post a new thread with the details and pictures if you can.
These are my thoughts on you hens issue. I hope I have been helpful.
God Bless