Feather lose in 26 days old chick

[Cholesterol man]

Hi, I have 3 chicks Who are 26 days old. They have feather lose in their shoulders and chest. Feather lose in chest is severe as it is naked. is it molting or parasites, please help me

 

[PippinTheChicken]

Photos?
They could just be getting their adult feathers.
What breeds are they?
What is your setup like? What's the size? I'll need pics of that too

 

[Cholesterol man]

Please take a look at my another post with same title. this post is a mistake. my other post has pictures in it. but now, I will answer to your questions.
Their breed is leghorn.
In brooder, There are is a dust bath, newspaper bedding, a bowl of water with pebbles in it and a commercial feeder. On top of the brooder I have putted a mosquito net to avoid escaping.
area of the brooder is 2.4 square
feet and it's height is 20.5 centimetres

 

[coach723]

Other thread is here: https://www.backyardchickens.com/threads/feather-lose-in-26-days-old-chick.1484308/