Welcome to BYC! Please make yourself at home and we are here to help.
Sorry about your rooster!
Is he molting? Does he have lice or mites? Have you wormed him recently? What does he loo like? Here is a checklist to use on him to see if he looks sick.
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Eyes-Clean, bright, alert and no fluid emerging out
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Nostrils-Clean with no unusual breathing sounds and no fluid emerging out
*Comb and wattles-Clean, glossy and plump
*Neck and head-Alert, upright and not sagging or lopsided
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Feathers-Clean, slick and well-preened
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Crop-Full and rounded in evening, empty in morning
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Legs and toes-Sturdy, firm, not lopsided and scales should not be raised (Lifted scales can be a sign of mites.)
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Vent-Clean and moist but not very wet
*Droppings-Firm, white capped
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Body weight-Appropriate for age and breed and not over nor underweight
You may want to also post here for more insight.
https://www.backyardchickens.com/f/10/emergencies-diseases-injuries-and-cures