Had same symptoms...got tylan 50 from tractor supply. Insulin needles from Walmart. O.5 ml or o.5cc or in insulin needles I/2 syringe if it's a 1 cc (or ml) size. Give shot in breast or neck..my sick chick didn't flinch. Gave 5 doses in five days....As far as tetracycline I put 1/8 tsp in 1...
I have a sick hen that I have been hand feeding.....especially cut up grapes and watermelon. Sprouts that I grow and a dropper for water with some antibiotics in...put on her top beak and she swallows it. Good luck with your hen.....