Please Help!

[Mar_ducks]

My chickens have become more and more aggressive over the past few weeks. This has resulted in a few of them getting injuries (specifically in their eyes which had caused infection). Why causes a sudden onset of aggression? What can I do to help stop this behavior before more of my chickens continue getting injured and needing treatment.
They always have access to food and water, and they free range all day long.

 

[BoundlessLove]

Hi many chickens do you have and what size is your coop and run?
Also, How many are males and how many are females?
You do not refer to their age; however, it sounds as if they are possibly juveniles.

 

[allosaurusrock]

Agreed- what is your rooster ratio?

 

[Mrs. K]

And pictures of your set up!

 

[Mar_ducks]

Hi many chickens do you have and what size is your coop and run?
Also, How many are males and how many are females?
You do not refer to their age; however, it sounds as if they are possibly juveniles.

I have 12 chickens in a very large 15x8 run. They are in the run at night and get let out every morning by 8:30 am. They then free range all day. They have a large nesting box structure we made that has 9 boxes.
They are young. About half are nearly 1 year and the other half are 9 months old. No males, all females.