With the eye looking sunken, it looks like conjunctivitis or pinkeye, that might be caused by mycoplasma gallisepticum (MG.) Is the chick having any gasping, sneezing, or being very lethargic or sleepy? Make sure that it is drinking plenty of water, and you can also add water to a small bowl of chick feed and offer it often. Tylan 50 injectable can be used orally, but you need 3 ml syringes with 18 or 20 gauge needles to withdraw it from the vial. Give 0.25 ml (1/4th ml) orally 3 times daily for 5 days. It may chill and need a little extra warmth as well. Use the antibiotic ointment as well. Tylan 50 and Terramycin eye ointment can be found at most farm stores and TSC.