So sorry about your roo...I'm telling you what, that respitory crap is EVIL...It takes them down sooo quick. I bought the bottle of Tylan 50 at the feed store and I had some diabetic needles I used for my dog. Mine go up to 1/2 cc but you can buy some at the CVS or wlagreens. Just tell the pharmacist what you need it for. I would get the ones that go up to 1/2 cc cause that's the amount for a grown bird and you can always use less for babies, teens ect. You fill the syringe, tap out the bubble so it goes to the top, squirt out the air, inject the bird into the breast meat pull back the plunger to make sure no blood goes into the needle( that would mean you hit an vein and you don't want to do that, this medication goes into the meat only...if you did hit a vein remove and re-insert needle) Slowly inject the medication, remove needle and gently massage injection site. You want to alternate the injection site as this is strong stuff and if too much is injected into the same spot it can cause deterioration or the flesh. Just do left side first day right side next day and so on. This sounds difficult but truthfully my 13 yr old does it with ease. The needles are so thin they don't even flinch. Some people give the medication by mouth but I have noticed better and faster results if injected, and with a respitory infection we all know how important it is to get the situation under control. Again, sorry for your loss, I myself lost one to R. I. and have fought this diabolical killer numerous times. It can just pop up for no reason, no new chickens, or environmental changes, just POOF..everybody is snot nosed and hacking.