Coccidiosis is one of the most common threats to young chickens, and it can move fast — a flock that looked fine yesterday can have sick, hunched-over birds today. Here's how to spot it, treat it, and keep it from coming back.
What to Watch For
The telltale signs are bloody or dark, tarry droppings, lethargy, ruffled feathers, pale combs, and chicks that stop eating and huddle instead of exploring. Coccidiosis hits hardest between 3 and 8 weeks of age, when a chick's immune system hasn't built up resistance yet, and it spreads through damp, dirty bedding where the coccidia protozoa thrive.
Step 1: Treat With Corid (Amprolium) in the Water
Corid is the standard go-to treatment — it's an amprolium-based powder or liquid that you mix into drinking water for 5–7 days. It works by blocking the parasite's ability to absorb thiamine, which stops it from reproducing. Follow the label dosing exactly, and make sure medicated water is the only water source available so every bird gets a full dose. You can find Corid at most farm and feed stores, including Tractor Supply.
Step 2: Support Recovery With Electrolytes
Coccidiosis dehydrates birds fast, and Corid itself can be tough on a stressed gut. Adding a poultry-specific electrolyte and vitamin supplement to their water during and right after treatment helps them bounce back faster:
🐤 Shop Purina Electrolyte & Antioxidant Supplement for Poultry
🐤 Shop Rooster Booster Vitamins & Electrolytes with Lactobacillus
Step 3: Clean House
Coccidia oocysts survive in damp bedding for weeks, so a full bedding change is non-negotiable. Swap out litter, scrub waterers and feeders with a mild bleach solution, and let the coop floor dry out completely before putting fresh bedding down. Keep future bedding dry — damp litter is the single biggest risk factor for a repeat outbreak.
Step 4: Prevent It Next Time With Medicated Starter Feed
If you're raising new chicks, a medicated chick starter feed containing amprolium builds up low-level protection from day one, which is a lot easier than treating an active outbreak later:
🐤 Shop Manna Pro Medicated Chick Starter, 5 lb
One Important Note on Timing
If you're planning to deworm your flock too, give them 3–5 days on clean water after finishing Corid before starting a dewormer — back-to-back treatments are hard on their gut. We break down exactly how in our deworming guide.
Want the full week-by-week playbook for keeping your flock healthy year-round — symptoms to watch for, treatment protocols, and prevention checklists for every common backyard chicken illness? Our Homestead Flock Health & Troubleshooting Guide covers it all in one place.
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