I'm sorry that your question wasn't answered in a timely manner. It's necessarily conjecture but when more than one chick is showing evidence of ocular disease, an infectious respiratory agent is most likely. In any case of respiratory illness, it's important to know if you're dealing with a viral, bacterial, fungal, or parasitic disease. The treatment for one disease may be ineffective or even harmful for others. Outward signs may appear similar to the flock owner. To make a diagnosis, your avian-oriented vet (please see here: www.aav.org) or county-extension poultry personnel can perform several tests including bacterial cultures of the airways, blood tests, and necropsies (post-mortem exams) of dead birds if they are available (refrigerate - not freeze - their bodies until they can be brought to the vet or your county health officer).
Presumptive therapy with Duramycin-10 (tetracycline) available in feed/agriculture merchant stores is appropriate for affected flocks. I would initiate such therapy to these chicks and I would continue it for 10 consecutive days. A single bird is better addressed with an antibiotic prescribed by your vet that you could administer directly into the beak or by injection into a breast muscle.
Small poultry flocks are susceptible to a number of respiratory infections. Some of these produce extremely mild illness while others may result in a high number of deaths. Common bacterial diseases include fowl cholera (Pasteurellosis), chicken coryza (Haemophilus paragallinarum) and avian mycoplasmosis (Mycoplasma gallisepticum); infectious bronchitis is a common corona viral infection. I conjecture that the chicks are exhibiting mild avian mycoplasmosis symptoms but I can't confirm this without testing them.
It's best to approach the diagnostic process with a clear sense of a bird's financial value to your operation. Although some services might be available free of charge through a county agency or land-grant extension office, the expense of some diagnostic tests and treatments can add up quickly. While it’s always worth your time and money to identify a bacterial or viral infection that could potentially impact more than one member of the flock, this might not be the case with a condition that only affects one bird. Please respond with further questions or concerns if you wish.