I'm about to go and buy 2 nine month old hens from some one, and I already have 4 chickens that I incubated and hand raised. I asked the lady if they had been medicated for disease and pests, such as mites and she said yes. I explained that I hand reared mine and I was slightly concerned that they would develop something from me bringing in 'outsiders'. She said all her chickens get treated for mites and diseases annually, and that even I could have mites from MY chickens, even though their coop is new and the garden has never had chickens before and they have never been in contact with other poultry. Are mites in the ground and grasses like ticks or hookworm etc? I don't want to give my chickens any medicines (unless desperately necessarily), I want to keep their health as natural and medicine-free as possible. They are 18 weeks old and I feed them organic layers pellets and never use any chemicals in my garden and they are looking beautiful! If anyone can shed some light on my mite concern that would be brilliant, many thanks.