I've read but no clue how true it is but straw, being hallow, the mites burrow in it?  
I use pine shavings in the Chicken House (8x12x7), my girls (4) are confined for their safety. DE in the nest box and CH as a preventative but I also dust my girls with Garden & Poultry Dust monthly, rotating with Sevin 5% during the summer months. Winter I use a mix of all three to dust them.
Don't give up, keep up the treatments.

	
		
			
		
		
	
				
			I use pine shavings in the Chicken House (8x12x7), my girls (4) are confined for their safety. DE in the nest box and CH as a preventative but I also dust my girls with Garden & Poultry Dust monthly, rotating with Sevin 5% during the summer months. Winter I use a mix of all three to dust them.
Don't give up, keep up the treatments.


 
	 
 
		 
			
		
		
		
	
	
			
		 
			
		
		
		
	
	
			
		 
			
		
		
		
	
	
			
		 
 
		 
			
		
		
		
	
	
			
		 
 
		 
 
		 
  I agree the the other posts. I had some birds that were severely infested. I thought they were just molting but weren't getting their feathers back in when I discovered they were loaded with mites. The first thing I tried was DE. The birds weren't improving and still had mites. I first discovered them in only one coop but eventually found them on birds in another coop. I dusted the birds and the coops with the DE and no improvement. I did use some seven dust that I had but it was almost gone but it did help. I did some research and came up with permethrin, which is the pyrethrum on steroids. It lasts longer than pyrethrum. Wild birds can bring them in if they have access to their coop. I used the dust on the birds and in their nest boxes and sprayed inside of the coops, every crack and crevice, on and under the roosts, ceiling, walls, floors, anywhere the mites can hide. It's best to clean out the coop before you spray. I use pine shavings in my coops. Since it so cold you can spread the dust around and dust the birds well. Wear special clothing including a mask and gloves. I did a weekly spraying for awhile and put permethrin dust in the nest boxes, originally sprayed the birds getting under the wings and worked it through their feathers with gloves which you can also do with the dust. Slowly the birds began to recover and get their feathers back in. I think if I hadn't treated with the permethrin when I did I probably would have lost some birds to the mites. The birds were in bad condition. I did originally bathe the worst birds with flea shampoo which did help but did not get rid of the mites. If you want to bathe your birds, every over-the-counter (OTC) treatment for head lice for people contains either pyrethrins (Rid or Triple X) or permethrin (Nix). They are effective treatment. Both only kill live pests, not the pests eggs. The added benefit was no egg withdrawal period. AS you discovered,
 I agree the the other posts. I had some birds that were severely infested. I thought they were just molting but weren't getting their feathers back in when I discovered they were loaded with mites. The first thing I tried was DE. The birds weren't improving and still had mites. I first discovered them in only one coop but eventually found them on birds in another coop. I dusted the birds and the coops with the DE and no improvement. I did use some seven dust that I had but it was almost gone but it did help. I did some research and came up with permethrin, which is the pyrethrum on steroids. It lasts longer than pyrethrum. Wild birds can bring them in if they have access to their coop. I used the dust on the birds and in their nest boxes and sprayed inside of the coops, every crack and crevice, on and under the roosts, ceiling, walls, floors, anywhere the mites can hide. It's best to clean out the coop before you spray. I use pine shavings in my coops. Since it so cold you can spread the dust around and dust the birds well. Wear special clothing including a mask and gloves. I did a weekly spraying for awhile and put permethrin dust in the nest boxes, originally sprayed the birds getting under the wings and worked it through their feathers with gloves which you can also do with the dust. Slowly the birds began to recover and get their feathers back in. I think if I hadn't treated with the permethrin when I did I probably would have lost some birds to the mites. The birds were in bad condition. I did originally bathe the worst birds with flea shampoo which did help but did not get rid of the mites. If you want to bathe your birds, every over-the-counter (OTC) treatment for head lice for people contains either pyrethrins (Rid or Triple X) or permethrin (Nix). They are effective treatment. Both only kill live pests, not the pests eggs. The added benefit was no egg withdrawal period. AS you discovered,  
 
 
 
 
		 
 
 
 
		 
 
		 
 
		 
 
		
 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		