Sick Chicken with tail down, lethargy!

[10HensandaRoo]

So about yesterday afternoon, I noticed my big hen, Burrito was looking lethargic, sitting in the coop. For reference, she is a 4 year old Buff Orphington. I was immediately alarmed as this is of course odd during midday. Later on the chickens got let out to free range and I had to pull her out of there to see how she would be outside in the yard. She was making soft broody noises, which was also interesting. With Burrito I also noticed she had a bit of green poop residue on her fluff below her vent. Later on she stood in the same place for a long time, and another hen tried to peck at her, which made me more concerned, as Burrito is the head hen and a big girl who doesn't take orders from the other ones. This morning she is sat on the woodchips in the coop, appearing to sleep, normal breathing patterns. Burrito is kinda more quiet and slow moving in general, but this is not at all normal. I'm concerned it's maybe her egg bound or another thing, but I don't want to medicate her randomly so any help pinpointing what it could be would be much appreciated.

Thanks!

 

[nuthatched]

What's her diet?
Has she laid recently?
How's her crop feel?
Has she ever been wormed?

 

[10HensandaRoo]

What's her diet?
Has she laid recently?
How's her crop feel?
Has she ever been wormed?

She eats her usual layer crumbles, foraging in the grass daily, mealworms daily, and over the past 3 days it's been some bananas.
As for laying, I can't say that I've seen her in the nesting box lately, and by lately I mean the time she has been sick and a bit before. So perhaps 3-4 days.

I've checked her crop just now and its completely empty.

I have never wormed the chickens before in the four years we have had them.

 

[10HensandaRoo]

I just took her out of the coop this morning and she has her tail up only slightly higher, ate a little bit of seeds and mealwooms, has walked around a little bit. Stool is green with white. She is somewhat interacting with the hens through the chicken wire.

 

[10HensandaRoo]

 

[10HensandaRoo]

I separated her from the flock and put her in the hen hospital/broody coop with some Apple cider vinegar water and some food. She drank water when I initially put her in there.