Converting goat fencing for containing chickens?

I moved to a 2 acre "ranchette" property. There is an existing 10x 15 foot corrugated metal shed that I could use for the chickens I plan to get soon to roost in. (I am leaning towards getting Guinea hens) There is abt a half-acre fenced area surrounding this shed, but it is 4 ft high goat fencing with 4x4 openings. The posts actually are about 5 ft high. So I need to convert this fencing to use to keep chickens in, and predators (mostly wild dogs here) out. I am thinking its better to have a 5 ft. fence, as I hear sometimes the "fliers" can get over a 4 ft fence, and I don't want to have to keep wings clipped. I think a 4x4 mesh/opening is too big for a smaller/ younger chickens, isn't it? I am thinking that I can do one of two things. I could get 100ft. rolls of welded wire fencing, 5 ft. high, with 2x4 openings. Or I could get 60 in. poultry netting (galvanized) with 1 in. hex. The chicken fence sells for 80.00 per 100 ft in that height. I don't have the experience with fencing to know what is the best and most cost effective. But I am thinking the poultry netting, since it is so thin, might be rusted/shot in just a few years, whereas the welded wire would last decades. The poultry netting would keep even the little peeps in, but I can't see paying a few hundred for fencing that would have to be replaced in just a few years. What is the best solution?

You are using some what the same fence I have used for years with great luck, however I think you will soon find that clipping wings spring and fall is a worth while effort. If you have wild dogs, I suggest you avoid the netting and get a good guard dog for the birds. dogs dig in, birds fly out, a good guard dog is worth a years worth of chickens, as that is how long it will take you to replace your flock that is now laying with new chicks that aren't.
Shelter depending on where you live is important, however a place to get out of the wind and roost off the ground is main priority. A building is less important then a wind break. I live in Iowa, where its cold, windy, wet and basically your average hell on earth. My birds don't have a hen house per-say. They have roosts and a place to get out of the wind. The main cause of loose is predictors, not weather.
If you have never had poultry before may I suggest you don't start with Guinea hens. They are a trick to raise. Keeping them in or even on your property can be a trick. If you start out with chickens, and put some guinea chicks under a broody hen, the guinea will identify with the chickens and stay with them.. ok.. they will stay closer then they would have other wise. The trick is to get your animals to work for you, not you work for them.
Good luck.