Do you need to give a bird an injection?

If you do, this is a good link and this is how I learned.
I get my needles and suringes from the Tractor Supply Store.
I personally like the 1 inch long size #20 with a small 3cc syringe.
Also If one of my birds seems to have a respatory illness I dab thier beaks with VetRX that I purchased from cuttlersupply.com As a precausion I clean the pens add a heat lamp at one end for them to go to if they want, and I disenfect the wateres and add a tablespoon of apple cider Viniger to the water this kills germs and may prevent it from being passed on the the others.
Give your Adult silkie 1 cc/ml of Tylan 50 under the skin of the breast for 3 days, 5 days for serious infections.
How to give an injection from the Easy Chicken site
Link to Instructions