Unfortunately, there is no such thing as a McFadden coat of arms. This is a common myth. Coats of arms were granted to individuals, not to everyone with the same surname. Only direct descendants of such an individual would have a claim to their coat of arms. So even if there had been a McFadden that used one, it would only apply to a very tiny percentage of McFaddens. As it is, we have yet to come across any evidence that someone named McFadden had a coat of arms. It’s worth pointing out that at the time that coats of arms were coming into use, the McFaddens would have been Gaelic warriors rather than knights.