As I recall, that stuff from WalMart is permethrin/permectin.I have poultry dust and 50 pounds of DE mixed in.
for some birds i can catch i now put flea/tick dog drops on my birds and it REALLY WORKS. i added an extra dose a few days after the first kill and for 3 months now those specific birds are still lice free and not miserable compared to their buddies.
I went to costco and bought a pack of large dog and put 3 "drops" on the bird. one under the belly near the vent, one on the back of the neck and one on the saddle.
Warning! after the first drop the lice start running and will get on you as they try to escape. this stuff killed the eggs too.
I gave up on the "natural" options and just apply to the new birds i get and to chicks that are moved out of the brooder to keep them lice free. i just have too many birds to actually do this to them all but i snag a few every now and then and apply some. i always dose the broodys a lot because they sit in different nest boxes and spread the lice around.
all birds i applied this stuff to is alive and doing well. just make sure to buy the dog one, the cat one is formulated a lot differently.