I have applied a special antibiotic liquid into his half closed eye so hopefully that will help him, I also noticed he has a black scab just under his eye lid meaning it potentially was a scratch or something and less likely to be an infection as only one of his eyes are showing this issue?
Having checked the rest of the flock are normal so unlikely to be bird flu as it kills quickly and none of my neighbours who also own chickens have had issues, so hopefully it’s not