
I read an account of this Cathedral in my EuroVelo Guide and thought “on drugs or mad?”
So, I checked Wikipedia. (Same madman or drug addict?).
So, I took a detour and inspected the site myself.
Here is what Wikipedia says:
A miracle is attributed to Dominic according to which two beheaded cooked chickens resurrected to testify in favor of a pilgrim wrongly accused of theft. A pair of descendants of the chickens are kept at all times in the choir loft of the cathedral.
Surely not?

Zoom in and you’ll see the rooster and hen – in the cathedral.
I asked the nice man who had charged me €5 entrance “Do you believe the BEHEADED COOKED chickens were resurrected?”
Like the faithful local you’d expect, he said yes.
I’m going for a beer.