I used the Big white bag of wood shavings From TSC $4 and its a huge bag! It has big shavings so no fear of them eating hte wood. It is cheap and worked for over 4 weeks with 51 chicks with out changing! I just stirred it up a lil to help sink the droppings. I just cut open 4 big boxes to make a wall 5 ft circle. Lined it with plastic and filled with shavings. I put a brick in before the shavings to put the waterer on. (Thank God I did) When they started to try to fly they would spill all the water. I am so glad I put down the plastic! It made changing the shavings so much easier and kept the carpet clean and dry! I used a dust pan to shovel up the shavings and put in a trash bag. Then just put in the new ones. I could clean and replace them all in about 20 min. I could have done it faster but i had to work around the birds. LOL I left them in the pen while i cleaned it. I just did half of it at a time. When they began to try to fly i just built a screen cover over the whole thing. I built an A frame to hang the feeder and waterer on. I just slid a piece of wire through the screen and hung them. I could reach in to clean and refill and make hight adjustments. I made a door of cardboard so i could get in and clean and get them out for 1 on 1 time. I spent a while each and every day to hold and pet every single 1 all 51! They are so sweet and gentle now!!! Holding and contact is SO important for a gentle calm bird!!!!! I cant stress it enough! Keep a low mono tone voice and just talk sweet to them. There was a great article in the back yard poultry mag. about sound pitch changes and what it means to chickens. It is so cute I amaze my wife by immitating the sounds they talked about. all the birds respond every time! They will come to me, run away, freeze in place( for a minute or more!) or even just settle down and relax! It is amazing!!!! My DW calls me the chicken whisperer. LOL
I made sure to pet them gently and slowly. I made sure to start out slow and work up to touching their neck. This is a very voulnerable and sensitive spot for them. It took me a bit but now I can touch their necks with out much notice. Most of them love to be held and pet. 1 or 2 will tollerate it but they would rather just be left alone. I try not to bother them too much but I will keep in touch. Just to make sure they know I am in charge and not to be affraid.
I hope some of this info will help.
Good Luck and God bLess!

I hope some of this info will help.
Good Luck and God bLess!