Ok, so I've used DE in the past, but that was BEFORE getting the lice. I had to give one of my roo's a bath the other day, and as I was blow drying him I noticed all these little reddish spots on his feathers (he's a white Silkie), and Upon closer inspection I realized they were moving.
So I flipped him over, looked at his vent, and sure enough, they were EVERYWHERE. They were NOT there the last time I checked my birds. So I made the trip outside to check the rest of the birds and oddly enough, not everyone is infested. Some I found maybe one or two on, some I found absolutely nothing on, and some seemed to have a party going on around their vents. So, my question is, which will get rid of them faster? Should I just get a big ole bag of DE, or should I get some Sevin dust for now? I can't get to a store so it has to be delivered, and all I can find online is Sevin 5 dust, not Sevin 10. I want these pests GONE A.S.A.P. I know the DE has to be food grade, that's what I've bought in the past. And I plan to dust both my flocks, even though my Standards are clean and far away from my Bantam flock. But the wild birds are EVERYWHERE, so I know that's where the bugs are coming from. I plan to deworm the flocks soon, just to be safe. Oh, and I bring my little babies outside too to enjoy the weather now that it's nice, and I'm sure the lice are in the grass all over the yard, not just in the chicken areas, so can I, or SHOULD I dust them too? One group is 6 weeks, one group is 4 weeks, and I have a little group that is about a week and a half old, but I haven't taken them outside yet. Best advice in this situation? I want these pests GONE!!!

