Well yes and no, lol..
Yes 5 acres will support 20 chickens.
Yes 20 layers will more than give enough eggs for 2 people, even in winter.
No..having bigger breeds will not cut losses from predators like Coyotes. You should not have a problem with your cat or hawks with all but bantam breeds.
I would not count on them foraging for their entire diet, you will still need to feed them.
Being in the woods I would also think you'd have more predator problems such as raccoons, skunks, etc.
wooded areas are predator areas, plain and simple.
Free ranging is an "accepted loss" way of raising chickens. Unless you stand gaurd, sooner or later you will lose some. We lost 10 in one day to small domestic dogs..so imagine what a coyote could do, or worse a pack of them?
If all your after is Egg production, I would not be looking to heritage or designer breeds but rather some of the purpose needs egg producers. I believe the "freedom Rangers" are the ones bred to be good foragers as well as producers. Production bred birds will have a better conversion than heritage or designer bred birds.
Another note on predators. You might also consider smaller birds of a dark or partridge color that can hide better than large colorful breeds.
I thought the Freedom Rangers were meat birds?
There's a brown Leghorn that might be able to hide better than the white ones. Red stars and Rhode Island Reds are supposed to be great producers. AFAIK, Leghorns have the best feed to egg conversion though.
I agree, with higher production birds you'll need to feed them. Wild chickens did not lay as often and did not need as much nutrition. Most birds you buy today have been bred for production which requires more nutrition.
I think getting larger birds won't decrease the odds of a predator attack. It may even worsen the odds since the larger breeds won't be as agile or able to fly away from problems.
You'll certainly need a good coop. Seems most people lose birds to predators at night.