Do you know what kind of spray was used, liquid, aerosol,...? Also is it a baby and pet safe kind, specifically is it rodent safe? They normally will tell you (or you can look up the product) how soon after it's safe, but I would say at least a day or two if it's the kind that you don't have to leave the house for, if the kind you need to leave the house for then I would say at least a week. Also what all was sprayed? just around the baseboards or was the floors and walls done as well? I would wipe down anything that was sprayed that the chin could come into contact with, then wait for that to dry before allowing the chin back in the room. I would also cover the baseboards to make sure the chin can't chew them.