They have wood chips from tsc. They have discovered their love of digging and get way down in the bottom where the dust and food particles settle. today is the first time I noticed sneezing.And it is possible that their brooder is dusty and making them sneeze. What bedding do you use? I use sawdust for the chicks and they havenever tsneezed with that, but thats the only bedding I have ever used is sawdust so I dont have experience with sand and chicks. The chicks dont get the privilage of sane yet lol, only the adults