Sand is an excellent medium for chickens and covering concrete. I love sand. It is easy to clean, it stays dry, it keeps the flys away, you can hose it down in the summer and keep the birds really cool, there are no smells from poop, and it has tiny stones for the gizzards. The birds love to scratch around in it. I use it in coops, runs and even the nest boxes!!
Here is a great link to using sand that will help you out...
https://www.backyardchickens.com/t/444759/got-sand-you-should
Good luck with all your new poultry adventures and if you have any other questions, that is what we are here for!