I was required in order to be able to sell birds/hatching eggs at swaps and such. My flock was around 40 at the time I was tested. A friend of mine was the tester. They take a blood sample from each bird and put a drop of antigen on the tile they do the culture on with a heat lamp over it, within a few minutes you have results either positive or neg for t/p. Keep in mind only a few birds can be tested at a time, so for me it took the better part of the morning into afternoon to get all the birds here done. Like others mentioned it may not be required in your state or location.