In the Miami? Is that even allowed? Guineas are noisy, especially when penned full-time, so from the time that they are about 7-8wks of age on you can expect a lot of noise from them until they are processed/butchered. You can look up Guinea Fowl sounds or calls on youtube if you are not familiar with how noisy they are..
If the noise isn't an issue for you/your neighborhood then you'd need to raise the Guineas in a secure, predator proof enclosed coop and run... otherwise yes they will fly away. Welded wire and hardware cloth (a layer of each) are probably your best bet for keeping the Guineas safe, and even a few strands of electric fencing on the outside of the coop/run to help ward off the feral cats or any other predators.