Chicken Breathing Problems

[blugraphic]

My chicken is breathing has been breathing from mouth quickly since two weeks. iam giving her anibiotics in the water but no improvement appears on her health. It seems to breath more heavily when it do some effort.
please help. Is there special food i should give her ? anything i can do ?

 

[TaylorHobbyFarms]

What is the temperature in the brooder? You aren't using cedar shavings, right?