I have been doing the deep litter method and each week put down Sweet PDZ and DE with the pine shavings. My DH is running electrical out there so we could have a electric vent instead of the current roof vents we have. The last time I totally cleaned out the hen house and wiped everything down (this was about 4 weeks ago) I thought it would take care of the problem. I hosed everything off dried it really well and put new shavings and PDZ and DE down. In about a week the smell returned. What am I doing wrong??????????