how were the workers treated when you construct the Great Wall?

As far as I know, they were treated badly and in Qin Dynasty, they were treated as slavers.

All I know is that millions of workers died during the construction...

Ahem,it's not "millions"there weren't even that many people. Only about 300,000 people built this and 10,000 people died,not "millions". Also, the peasants weren't treated with care.Theyworked all day even in harsh weathers. It was very dangerous. "Nobody like a Miss Know it All"well i don't actually care.