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Is he able to see with his comb hanging over like it is?
Can you get photos of his eyes?
Is his beak cracked or broken, it's hard to tell in the photos.
Look him over for other injuries/punctures that may be hidden under the feathers.
Where is he missing feathers? From the back, tail?
I would definitely work on hydration, giving electrolytes or sugar water.
Syringe drops into his beak periodically working him through shock.
You are giving Corid? It's o.k. to give it won't hurt him, but it's not an antibiotic and will not help with any infections/injuries or wounds. It's a Coccidiostat used to treat Coccidiosis which is mainly seen in young chicks.
What does his crop feel like?