After observing and feeding him today I think he was just malnourished and all he needs to do is eat more here. I'll still dewormed him and treat my whole flock with Corid.
Corid powder dose is no less than 1.5 teaspoons per gallon for 5 days, then 1/3 teaspoon per gallon for 7-14 days.
Corid liquid dose is 2 teaspoons per gallon for 5 days, then 1/2 teaspoon for 7-14 days.
Make fresh daily and it must be their only source of drinking water.
-kathy