Discharging fluid out of hens mouth, Hen with respiratory infection?

[Mehran_kou78]

Hi
so i got this hen( fighting breed) from a friend and i felt like there were some small amount of fluid coming out of her mouth although she looks well and eating and she started fighting my other hens and wheezing alot (looked unusual) i felt like she might have respiratory disease?
Deep inside at top of her mouth wasn't looking clean can this be a respiratory infection? Is it contagious??
Sorry if the pictures aren't clear

 

[Mehran_kou78]

Also i have to add that she is probably +4 years old

 

[Mehran_kou78]

Anyone knows anything??