Rooster with a Swollen Eye

[StarLightFarms]

Noticed my roosters left eye was swollen last night. Today it was completely shut. It was hard the get a good look but some yellow discharge in the one corner. It also looks swollen above/around the eye. Just wondering what it could be, what to look for etc. Mostly want to make sure its nothing contagious. I've never dealt with an eye issues before. First picture was from last night, two other from this afternoon. The other eye is completely normal.

 

[StarLightFarms]

First picture last night. Others from the afternoon. Other eye is completely normal.