That's the stuff. Many of the over the counter meds used on chickens are labeled for cows or pigs.
You'll need a syringe with a needle to draw the med out of the bottle.
You don't need to inject it, but can if you want to. It CAN be given orally. (as per reading online and according to my vet)
It's used for respiratory illness/infections. Some of those infections may be viral and will have to run their course, but often they develop secondary infections and this will help with that.
I give 1/4cc to 1/2cc for pullets (adjust by age/size. Half grown to nearly full grown can do 1/2cc, etc) , 1/2 to 1cc for adult birds, depending on size. Large sized adults (brahmas, etc), I'd go for 3/4 to 1cc.
I give it orally. I draw it out with a syringe, then use small dosing syringes to give it to them. I just "inject" the dosage into the smaller, needless syringe after drawing the dry dosing syringe back to the right dose, stick the needle in the small hole at the end, fill up the dose.
They can be tricky to dose orally... wrapping in a towel works best. There's also usually less of a struggle if you pull them off the roost at night. I make sure I get the syringe all the way to the back of their throat and even *down* it a little, to bypass their trachea so they don't inhale it.
I have given it to them by injection... but have read conflicting information on whether to inject into muscle(breast) or under the skin. I opted for under the skin at the back of the neck... the ones dosed this way were easy to inject (didn't even flinch), but were obviously sore and didn't want to move their necks much until the next morning. (it's a very thick med and will need a 20gauge or 22gauge needle) If I tried it again, I'd probably choose somewhere other than the neck... maybe the wing web OR just under the skin on the breast...but not into the muscle.
I would use Tylan 50 on birds that were sneezing, raspy, gaping to breathe and/or had nasal discharge with it. Particularly if they acted listless or their behavior wasn't up to par... especially if this went on for more than two or three days.
Give the dosage for 5-7 days...but, if you haven't seen any improvement in 3 days, what you're treating may not be sensitive to Tylan.
Watery eyes and noses are the things that seem to dry up first, and then sneezing lessens. Usually, they act much perkier by day 3.
How long I've dosed them kinda depends on the symptoms. If there is sneezing, I usually go 2-3 days after the last 'sick sneeze' is noticed.
I wouldn't think a raspy squawk is a trait of any birds. But if they have an infection, that can make them sound odd... even make a rooster's crow very sickly sounding. Pick them up and listen to their chests (like an ear muff!), do you hear clicking or rattling, or raspy breathing?
If the bacteria is sensitive to tylosin, then the Tylan might help, especially if the pus wasn't hard. So if it's what you have, probably okay to use it, though I'm not sure what an appropriate dose would be. 
