7 month old hen underweight and lethargic. Not sure what to do?

[Readstochickens]

I have a ‘runt’ hen, she’s 7 1/2 months old. She’s always been the smallest, she’s also the youngest by 6 weeks. She’s, what I was told, a Columbian Plymouth Rock. She’s smaller but more shockingly, she’s much lighter than the other 7 hens (2-14 months old (GLW), 5-10 month old (3 GLW, 2 Blue Plymouth Rock) Yesterday and today when I come out to give treats, clean the yard, run and coop, I noticed that she was alone and sleeping. I’ve never seen her sleep with her little head tucked in her wing besides at night in the coop so it was very odd seeing her doing that in the yard. Yesterday I noticed her bum looked a little wet as well. I always try to isolate her when I bring treats to make sure she’s getting them before I go back in. I don’t know what wrong with her and I’m really worried now. I’m thinking coccidiosis or worms? I find shell-less eggs about 3-4x’s a week sometimes despite calcium being placed in the coop, run and yard. What is your opinion? What treatment do you think I should try? I’m very worried about her, I love her. Thank you all!

 

[azygous]

You don't tell us much about her general behavior with the rest of the flock or if they have been aggressive with her. It's not unusual for a smaller bird to be bullied, and after a time, that becomes an instruction from the flock that she doesn't deserve all of the same privileges that the others have. Sometimes this leads to starvation because she has learned not to assert herself at the feeder. Have you seen this?

For starters, take her in and give her special feedings (eggs fish, or meat) today to boost her energy and get her appetite going again. Put a teaspoon of sugar in her water to raise her glucose, further boosting her energy. If you have poultry vitamins, add some to the water.

Tonight, return her to the flock, and tomorrow watch how she's interacting with the flock and if she's reluctant to eat at the feeder. This will tell us if she needs additional intervention of which I can guide you.

As for the soft eggs, you need to figure out which hen they're coming from. That hen may need additional calcium besides the oyster shell.

 

[Readstochickens]

Thank you so much! She looks worse today. Her comb is pale, she was moving her head oddly and she does get bullied. I am getting Pantacox and Fendbendazole. I brought her inside wrapped her in a towel and cuddling her! I gave her food and water with electrolytes in it. She ate the meal worms like crazy! It’s been raining since yesterday but in the 70’s so she has been damp on and off. (It’s dry in the coop but they love free ranging the yard anyway). Somebody on Reddit said she has failure to thrive and as much as it breaks my heart it could be so based on her low weight. I’m going to read more about it. Her sister who was hatched at the same time as her was attacked by a dog in May and her sister even back then was quite a bit bigger than her. Thank you for helping me, I really appreciate it. This is my first time owning chickens.