Chick holding tail down

[Kbantams]

I have a 9 week old rooster that has started holding its tail down, it’s always dropping downward for the past 4 days. Is this an injury or a symptom of illness? It’s eating, drinking, slightly loose poop but no blood and acting pretty normal, maybe a little less spunky than he usually is. We have had some colder than normal weather lately could this be affecting him? I keep them in a brooder outside with no heat during the day and bring them to the inside brooder at night.

 

[Eggcessive]

How cold has it been outside during the day? If he is standing around puffed up or hunched, and inactive, I might use some Corid in the water, just in case of coccidiosis. Dosage is 2 tsp of the liquid Corid or 1.5 tsp of the powder per gallon of water for 5-7 days. If he is not drinking enough, then syringe some during the day, and also give him 0.2 ml of the undiluted Corid once a day.