Gosh, I hope it's not pulverized poop! If it is, don't tell me.
I have 5 week old chicks in the garage.
We started them in the kitchen. No smell at all. We added pine shavings maybe once a week or slightly less.
At 2 weeks, we were going on vacation and moved them into our bathroom with the door closed. When we got back, there was a smell but it was pine shavings from the door being closed all the time.
At that time, they were 3 weeks, we moved them out to the garage. Still no smell at all. We haven't ever changed the litter, just added a bit maybe 3-4 times since we got them.
The dust didn't start til they were out in the garage, so I'd say sometime between 3 and 4 weeks old.
We have had unusually-warm, for our area, these past weeks. I usually turn off the lamp during the day. I switched last week to a 100 watt bulb. The temps are in the 60s at night here and they seem to still want the heat at night.