bird lice

Hey everyone, So, I found that my new pet pigeon has feather lice! Now, my pigeon is by itself as my pet in my home. I just got him/her from a breeder on the 14th. S/he was living outdoors with the breeder previously. I purchased some bird/lice & mite spray but still finding a few on my bird...

How do I check for mites and when is it safe to say that the bird is free of mites and bird lice? I have actually never seen any evidence of mites, what I had found were pigeon lice, that looked like this - http://www.warrenphotographic.co.uk/photography/dogs/08410.jpg