You can use either.
Me, I would prefer the injectable since you can give it direct oral dose and treat the individual bird while leaving them with the flock. The powder goes in the drinking water, so unless you separated him out, you'd end up treating your whole flock.
Injectable Tylan50 can usually be found in stores like TSC. Get a couple of syringes and a pack of needles too. You need the needle to draw the medication into the syringe, then take off the needle and direct dose him.
For symptoms of respiratory illness, the dose for Tylan50 is 0
.25ml per pound of weight given orally 3 times a day for 5 days.
Here's how to give oral meds
https://www.backyardchickens.com/ar...dications-to-all-poultry-and-waterfowl.73335/
Tylosin (Tylan soluble) can be used though if that's all you can find. Dosing is on the package.
You can order it online, here's one place that use to order meds
https://allbirdproducts.com/products/tylosin-powder-generic
If your TSC or feed store doesn't have Tylan50 but they do have Tylan200, you can use that too. The 200 is just 4X the "strength" of Tylan 50 but I can help you calculate dosing for 200 if needed.
Keep me posted on how he's doing.
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