http://forum.backyardpoultry.com/viewto ... &t=8009983 guinea fowl versus snakes
Seems from quickly reading the thread you'd need to have 3+ for them to be much use.
this looks like someone asked this on a poultry forum. there's even a link to a 2nd thread about it.
http://forum.backyardpoultry.com/viewto ... &t=7969713 guinea fowl versus predators.