quail with grey cloudy eyes

[aureterraterra]

Hello everyone, as a hobby we created an aviary to keep three quail in October, after two months one of the three quails seems to have gone blind, the area is the province of Milan (Italy), the cage is outdoors covered with a cloth, there is a manger and a drinking trough and a small den for shelter, the bottom is made of wood chips. Anyone have experience about it? Do you know what the cause may be? thank you

 

[aureterraterra]

here are the pictures in better quality I hope