Please help

[JLfarm]

I have ordered about 13 RIRs and now I have lost 4 3 in the last 3 days please help. Just the RIRs r dying the barred rocks polish and brahmas ( in the same brooder ) r fine.

This chick died 3 mins after taking this pic.

 

[Coins]

Maybe an infection caused it? The brooder looks kind of dirty.

 

[JLfarm]

Yes it was pretty dirty but would tha kill 4 little chicks about the same size. And I cleaned that's how I found him. Thanks