I need some help with the type of sand to use in our coop. It is a 12 x 12 converted horse stall. Very very nice and insulated with R30. We are in N Central Texas. I have been using just the dirt floor. It has been finished for about 3 weeks and I was so excited about it. We had 8 RIR about 3 months old now. So far 3 of them have died since putting them in their new house and one is sick and I am hand feeding it. I am worried that the existing dirt floor might have made them all sick with Cocci. Maybe, maybe not but I am wanting to put sand on top of the coop floor and outside run. I have no choice except what comes from a Lowes. My question is to the type of sand. I have read on here about using a sand that would be used to mix mortar. I can just see them eating that as they scratch around and it swelling inside them and killing some more. I only have 4 chickens left. I did see some sacks of all purpose sand at Lowes. Please offer your thoughts.