Soil gets compacted quickly and does not absorb and evaporate moisture well. Consequently it provides a breeding ground for bacteria.
You want a material that is absorbant with lots of surface to give the moisture off into the air again, that will keep the brooder dry and stink free.
OK, can we agree to disagree? There is probably nothing wrong with hemp bedding?? Just like there is nothing wrong with flake pine bedding in my opinion. Hemp bedding is Not a more "natural" bedding here and Most places in the world because it has to be shipped in---all over the world-----natural to me would be what the chicks/chickens are use to using is What I was Saying!! Chicks are use to using Nothing and what ever they are introduced to after hatching will be their first and I promise you wire floors do not hurt their feet if proper size any more than stepping on chipped up hemp or pine shavings even that awesome looking pellet bedding some use----that's gotta be rough---even walking on the ground hurts my bare feet more than walking on a steel mesh flooring used on a trailer. If you do a world wide survey you will probably find that MOST chickens are walking around on the ground----Dirt----sandy soil, etc---so to me that's more "natural". Sand does not pack and drains well and I have used it many times in coops, brooders, etc. I agree its heavier but its more "natural" than shipped in hemp----But to clear this up----I have NOTHING against Hemp but I am not going to have a unnatural bedding shipped in to my farm for a higher price than I can get local bedding for. If Tractor Supply starts carrying it and its about the same price----I will even try some for chick bedding but only after my wire floor brooders are filled. Everyone else can use what ever they want----I was Just stating Hemp is Not a natural bedding here.