The chickens moved outside.
When chickens are about eight weeks old, and the weather is above 70 degrees during the day they are big enough to move outside. I was ready for the chicks to move. When they first were placed in the bath tub they were no problem. The cute little chicks peeped around all day. At night we could sometimes hear them, but with the door to the bathroom closed they were no louder than birds in the morning and the older they got the more they settled down during dark hours.
As the got older there were two minor issues having them in the bathroom. When their downy feathers turned to chicken feathers the dust storm in the bathroom was intense. We placed an air purifier in the bathroom and kept everything closed. All the counters and surfaces were wiped down every three days or so as they were covered in dust. Once they were about six weeks old we stopped using the bathroom and shared with the kids. The dust was just too intense.
Baby chicks don't smell. But six week old chickens do. Once they hit the six week mark the smell intensified. Although it was never terribly gross, it was a sign they were ready to move onto bigger and better places. Outside, they would have more space, and fresh air. They were almost ready.