Deux coqs vivaient en paix ; une poule survint.
 Jean de La Fontaine (1621-1695), Fables, VII, XIII (1678).

I do not understand this maxime or citation or sentence - however it is classified. Literally : "Two cocks ( roosters, male chickens ) lived in peace; one hen ( female chicken ) appears/rises up." I found this while searching for something pithy about marriage. Please help to clarify. Thanks.

 

The full sentence is:

Deux coqs vivaient en paix; une poule survint
Et voilà la guerre allumée.

It suggests that as soon as the hen appeared, the roosters started fighting to win it.

 

Two cocks were living in peace, when a hen turned up.
And there the battle began...

The full text is available on http://www.jdlf.com/lesfables/livrevii/lesdeuxcoqs.