The non-chemical treatments don't seem to work really well, especially if you already have an infestation of ticks. Besides what you mentioned, If you can keep the grass mowed down short and take out as much cover as you can and give your birds free range time in the area helps. Some people say that spreading lime helps. If you are going with a chemical most people go with the permethrins. They are the main ingredient in most poultry dusts anyhow. And then there are always Guinea Fowl 
