I agree that you should give some amprollium or Corid to treat for coccidiosis. Here is some reading about it:
http://www.merckmanuals.com/vet/poultry/coccidiosis/overview_of_coccidiosis_in_poultry.html
http://www.the-chicken-chick.com/2012/12/coccidiosis-what-backyard-chicken.html...
