What is wrong with this rooster?

[Gracekelly76]

He is breathing with his mouth open and making gurgling noises, not eating much, his eyes are a bit swollen and his comb is dark purple

Some other chickens are sneezing and gurgling a bit now too but not as bad

 

[JenWillo]

Avian flu has some of these symptoms?

 

[Gracekelly76]

How is it contracted? No new birds have been added

 

[Tonyroo]

By wild birds droppings.

 

[am7039]

Sounds like possibly infectious bronchitis​