I don't understand your first question. Organic is the key. Chicken should be fine and fresh water fish that contain Omega 3's. Not farmed fish. I would stay away from beef altogether. Try to eat as much raw as possible. Can you find a good source of Trace Minerals? Also of multivitamins/multiminerals. I have emailed Utopia Silver to see if they ship overseas and have not heard back yet.
Okay, with regard to Yarrow, long term use can cause allergic reactions, so be careful. Yarrow is mainly an anti-inflammatory herb useful in treating stomach disorders. It is a traditional stomach tonic and digestive aid.
Yarrow is also used for blurred vision, bruises and pain, and the common cold and influenza.
With regard to Salix, are you referring to the Bark of the White Willow? This is used for pain. I couldn't find anything about parasites, unless there is a different herb.