she was fine on sat but today her poo is dark brown like tar and she is very sleepy i have took her out my flock for thy are all fine i have tryed to give her some soft rice and clean water but she just stands there sleeping help me please
It might be Coccidiosis. This disease affect the intestinal tract of chickens, causing droopiness, sleepiness, paleness, and sometimes bloody diarhea. Coccidiosis can kill quickly, so I'd start treatment as soon as possible.
The normal treatment would be Corid powder or liquid. However, I see that you are in Scotland, whereas I'm in the United States. I'm not sure what Corid would be called in Scotland. It might be known as Amprolium or Amprol, as Amprolium is the active ingredient in Corid.
If you can get Corid (Amprolium), the dosage will depend on the type. In the United States, both Corid 20%powder and Corid 9.6%liquid are sold. The dosage for the liquid is 2 teaspoons per gallon of water, and the dosage for the powder is 3/4 teaspoon per gallon of water, given for five days.
During the treatment, don't give dairy products, or electrolytes and vitamins. Corid works by depriving the protozoa that cause Coccidiosis of vitamin B1 (thiamine). Vitamins would prevent Corid from working correctly.