I have a flock of guineas on ten acres (just over the hill from you at Mothar Mtn, Frawley
), trained to come home every evening and rest on perches in the run. The run appears to be safe enough (although I am thinking of raising the fence higher and fortifying it with dogwire just to be sure).
However, after months of stable numbers (11 adults and ten keets) I have lost three or four adult guineas in the last week.
Because guineas range to the limit of line of sight of the house, the foxes can ambush them and pick them off from the surrounding bush. They only seem to get one at a time, but they are very bold about it, in broad daylight, especially in this wet weather, and the guineas don't seem to be very alert.
(Perhaps it is different in nature - natural guinea fowl flocks contain thousands of birds.)
I think I actually saw a fox attack today. I heard the guineas making a racket down the bottom of the paddock behind a stand of trees. I am pretty sure I saw a flash of red fur and then the guineas were flying (guineas only fly if they are REALLY scared). By the time I got down there, the fox was long gone and I found a few feathers lying about.
(Haven't had a chance to do a headcount yet, but I think there was only one bird taken this time.
Given that guineas need to free range, i.e., you can't keep them penned up unless it is a very big pen, I don't think guineas would be the answer, chriti, they'd just complicate the problem. I think your best bet would be to fortify your chicken run against fox attack, and if you do let your chickens out during the day, try to keep them very close to the house where you can keep an eye on them.
I'd also recommend looking for a decent fox trap. It is something else I have to look into myself, ASAP.