DE = diatomaceous earth, you can purchase it at most ag stores, I get a 50 pound bag for $25, it goes a long way. It helps to keep off flies, mites and I've read here even helps with their digestion. When I clean out the hen house, I sprinkle some on their bedding every other cleaning or so, perhaps 2x a month, and I also toss some into their run and their favorite "bathing places" in the yard. I have 13 large-breed chickens.
Straw, I use it in the winter, I like the insulating properties, then I switch to wood shavings in the warmer months. I have seen different qualities, so shop around, make sure your supplier is selling you dry, small wood chips (not great big pieces). Ask them to open a bag if you have any issues before you buy. I had poop boards in my "old" hen house but I have a new set up and haven't put them in, don't see a need. I clean the hen house out at least weekly, more if they're spending a lot of time in it like during colder days. Of course, we don't get nearly as cold here in Colorado as you do in Alaska....