Seasons greetings from down under! My two hens have had a minor lice problem for about a year now. Nothing serious, just getting annoying. I think we get them from the doves that fly in to feed on the chicken food. I'v treated the chickens repeatedly and they have adust bath which they use but show no substantial decline in lice. Should I add more sand to the dust bath? I'll try and get my hands on some ash. Any tips would be greatly appreciated thankyou. P.S, Here is a photo of the two kinds of lice we have.