HELP is this disease or molting??

[Craycraychickenlay]

It’s been weeks, it started with one chicken. The sick chickens heads look smaller?? And the eyes look bigger and darker than the healthy chickens.. The feathers around mouth and come look white. Pale comb. One of them is wheezing when breathing. My roosters comb has black tips.

 

[nuthatched]

Can you get pictures?
How old are your birds? What climate do you have?