[St_Thomas_Aquinas]

a P with crossed feathers (a 666 symbol also used in freemasonry)

It's a Chi-Rho, or X-P, the first two letters in the Greek spelling of Christ, one of the earliest Christian symbols.

I googled, "Chi Rho crossed feathers" and didn't come up with anything.

[MamaB]

I found one short sentence but could not find the reason. It is about a peacock losing its feathers. ????

[caww]

Look again...the symbol on the catholic church door are crossed feathers....