Very sick chick. Not moving, very lethargic.

[Rowzy]

When I let my chickens out yesterday morning they were all normal. When I locked them up my grey silkie was the last one in (which is abnormal for it).
This morning when I went to let them out the 12 week old silkie was sitting in a nesting box, not moving. There are no outward signs of illness, eyes are open, not runny poop from what I can tell (i dont see any poop in the nesting box actually). She isnt eating or drinking, and I know if she wont eat or drink she will die. Im afraid she will die before I can do anything.
I had another hen get like this a few months back. Im worried that they ate something poisonous.

 

[Cloverleaf Farm]

How did things turn out with the other hen? How old is the sick chicken?

 

[Rowzy]

The other hen died within 2 or 3 days. The chick is 12 or 13 weeks old.

 

[CrazyChickMom]

When my chicks did that I was advised to feed them plain yogurt. I have also had to use a dropper to give them water. By rubbing the side of the beak they will swallow. (just some advice I got on here over the past couple of days). Also, qaurentine immediately!

The really smart ones on here need more information. Like:

What are you feeding them
What does the poop look like
etc.

Good luck!

 

[Rowzy]

I am feeding all my hens layer pellet. They free range a few times a week.
**Edit** I was giving it water out of a dropper thingy and it pooped on me. The poop was a more solid orange with light yellow runs.
It drank some of the water thankfully.

 

[Rowzy]

I just went out and it was dead. Thanks for the advice, I tried but it just died before it had a chance.
Now, what causes this? Could it have ate something? I read the buttercups are poisonous (correct me if im wrong) and will shut them down from the inside... My pasture is full of buttercups could it have ate one?

 

[NotTheMomma]

http://www.chat.allotment.org.uk/index.php?topic=17568.0

View the pictures of poo here, and see if anything matches u with the orange poo you saw. Without me seeing the poo, I would guess probably worms since she died.

When did you last worm? What did you use?

Do they have access to the horse manure? Are they eating, scratching in it? When did you last worm the horses?

 

[Rowzy]

It was probably worms from those pictures

. The chickens have access to my whole property (including the horse pasture and mature piles.) The horses were actually wormed on wednesday and I worm them every 4 months as reccomended by my vet.
I know it has been too long since i wormed my chickens because I cant remember what I used. What should I use and how often should they be wormed?