That pic was probably taken at the old Avondale mill. They just now finished demolishing the last remnant, the old smoke stack, BTW. I worked, briefly, in a cotton mill in Talladega (Bemiston Mill), when I was young in the early 80's. The pic shown here was in the really rough days. Those older mills did not have any air conditioning and the spinning rooms (where the doffers worked) and were often so thick with cotton particulates that you could not see from one end of the room to the other. That is what you see on the boys clothing. Long term exposure to breathing cotton dust will give you "brown lung". It usually ends you life earlier than not.

Does anyone know what the boy on the left has around his neck?

I feel so sorry for these poor lads; obviously they had to work to help their families survive. Just looking at the fluff on their hats; I can only wonder how much of that stuff they breathed in and what health issues they had in later life.

Their faces tell the whole story in one picture.

The boy on the far right could easily pass for Beatle John Lennon. Could almost be the Meet the Beatles Cover

one who clears full bobbins, pirns or spindles holding spun fiber such as cotton or wool from a spinning frame and replaces them with empty ones.
A pirn is a rod onto which weft thread is wound for use in weaving.
There will be no more explanations, if you are a weaver you already know.