I just moved my 5 chicks to a larger brooder box with sand. The sand is Quikrete ALL PURPOSE SAND. It was recommended by an employee at Lowe's who uses it with his chickens. The chicks loved it at first. They pecked, scratched, and nestled in it for 30 minutes. Then, my strongest, top two laid over on their side in the "death position". They kept doing this over and over. Then a third did it. They were not dust bathing. They appeared in distress. I have lost several chicks and am familiar with the end moments. "Side sleeping" is not a good sign it seems. Any suggestions? Should I have washed the sand? Is it not natural sand and perhaps Quartz crushed and bad for their respiratory systems? Is this normal behavior, and I am just paranoid? I have lost the majority of this years chicks to what the vet said was most likely a virus. I would love to keep my five left. It has been such a labor of love.