Ahem... While the french revolution killed a lot of priests as nobles, it didn't suppress them, it broke the ties they had with Rome or other big european nations and mostly the advantages and privileges they had on laymen!
Today, a noble title (coat of arm and all) is still recognized by the french republic (if authentic) and shifting it to a surviving branch of a family is validated by the Prime Minister...!
For the priests and pastors it was more about links to Rome and Germany (and also about philosophy :-) )!

The roster was there since the romans, Gallus, the rooster, was the same word for the "Gaulois" and while most of the gallic tribes preferred the boar, many had the rooster as an emblem.
In the middle ages, the rooster was everywhere, catholics as local sorcerers or druids or shaman. I think it's really old around here :-)

There's a legend about Peter spitting a rooster because of the reminder of his failed oath, and all the others staying silent...It was common lore in the middle ages, but not of great influence, I believe, either in the french rooster or the ones on the spires of churches :-)

"What can I do, What can I write, Against the fall of Night". A.E. Housman