I know this is an old post, but my babies are 3 weeks old, turning 4 weeks tomorrow, and we have used hemp bedding from the get go, on brooder/coop, which for us are one in the same. It seems fine so far... The positives are it doesn't smell at all, not wet or moldy, and requires very little maintenance, we basically just stir it. I am thinking I might change it out since it's been a month, just to keep things fresh, but it could probably last much longer. For negatives, it tends to get jammed in the coop door which is annoying but not a big deal. It also inevitably falls out of coop into run space and area around coop a bit, even though we have one by fours up as blocks. They do eat it, not sure why or how to prevent this. I am looking for more info about this if anyone can weigh in. They are almost 4 wks/know what is food, so idk what the deal is.