I'm going to state my opinion here, not driven by any commercial bias.
I read a lot of forums, both in UK and France, and a lot of people swear by certain products - I even read one about spraying chickens with diluted bleach to rid them of red mite!!!
However, Unless a product is Licenced or sold for use on poultry then it should not be used on poultry. This is especially true if you are selling eggs (even at the farm Gate) as then you are classed in the eyes of the law as a commercial enterprise.
Now I'm sure that most of the "alternate" products that people use will have little or no detrimental effects, but is it really worth taking a risk for the sake of a few extra pounds? You need to know about the ingredients of these "Alternatives" in detail and any withdrawl period to apply for safety, as I'm sure nobody wants to hurt either the birds themselves or customers with unlicensed products.
I thought the majority of people on here were concerned with how their food is produced - and yet still advocate using just any old product because its cheaper.
I'm sorry if this appears as a bit heated, but this is a subject that gets me very annoyed. If anyone takes on the responsibility for livestock or Fowl for food production then they should also take on the responsibility to use the correct, licenced products and medications, which should be administered in a controlled manner with the correct equipment. If this can not be achieved for whatever reason then they should rethink why they are keeping the animals, and not publicise that they are using an unlicensed product to save a few quid.
My opinion for what it is worth, no apologies, spleen vented!