I found my chicken collapsed and then died

[Trinny]

this morning I looked in the coop to find my 1 year old polish hen spread out on the floor taking slow light breaths with her eyes shut her head was slightly responsive and 10 mins later she died I looked at her skin and it was coverd in mites could this be what killed her and is my flock in danger. about 5 days ago we found a small infestation of mites and powderd all the chickens and cleaned the house and sprayed it with a mite spray today when I cheeked there was more mites or is this from heat stroke my hens have lots shade but the air temp has been 28 degrees Celsius for the last 3 days please respond with ideas xx Trin

 

[Trinny]

I’ve spoken to my friend who lives in the same area and she lost a hen last night to red mites aswell

 

[getaclue]

I'd say mites.