Ceramic artists and those making pottery will tell you not to handle wood ash bare hand. They do NOT purify the potassium hydroxide. Even in concentration of 5-10%, it will saponify your skin!! I don't know where and why people think its okay! IT'S NOT!! If you don't believe me, make a solution...
HOLD IT!!!
Wood ash contains potassium hydroxide. Yes it will kill lice, fleas bacteria but DON'T USE IT IN A COOP. It is very very caustic and not good for any living animals!!
Take a half a cup of wood ash, add a cup of water, mix it really well with spoon. Stick your hand it for a less...