Guys/gals, he/she was talking about clipping the wing feathers as to not need flight netting over the top of the pen, not to free-range them. Yes you can, but I wouldn't trust a four foot high fence, I would want at least 5'. You could use electric wire around the outside to keep out ground predators, but you'd have to worry about hawks and the such, should be a big problem.
Whoever mentioned about tact, I agree. However, straight forward, clear, and yes, even blunt is how I like it too, it does away with most misunderstandings and further questions, but still with tact. Not that what you said was rude, Tony. Just I can see how it came across that way.