You're welcome. Sounds like a good way to give the meds. Giving Tylan into the muscle in the breast, the needle is inserted 1/2 to 3/4 inch straight in to the fattest part of the breast muscle. Rotate sides of breast daily. Since Tylan is for intramuscular use, I wouldn't use it subcutaneously (under the skin) in the neck, but some people do this with success. Injecting under the skin is 1/4 inch after pinching the skin up, and go straight in. There are many posts online about giving injections to a chicken. For IM injections in a chicken a 22 gauge 3/4-1 inch needle is best, unless it is penicillin which is very thick, then a larger needle (20 or 18 gauge) may be necessary. For SQ injections a 25 gauge 5/8 inch needle is used.