I read through this quickly, so sorry if I write anything thats already been stated. Welcome to BYC!
Mahonri said it best, DON'T free range birds that you are attached to, or those that you don't want to loose. Something will 
eventually happen, and we can do nothing to stop it, really. Hawks are there in the daytime, and they will get your birds in a 
heartbeat. I let some of my hens free range while I'm outside feeding/watering or cleaning, but never while I'm not around. 
As for the escaping, When birds 'escape' fencing, they will hop to the top of the fence, perch, then jump down on the other 
side. SO, to help prevent this from happening you might wanna make it really unstabble/uncomfortable or impossible to perch 
up there. I would recommend putting up netting/fencing that leans inwards at the top, leaning towards the inside of your yard, 
like you see in deer fencing. If you have a lower fence, make it higher. If the fence has a really nice, stable bar at the top, make 
it unstable/uncomfortable. You can usually prevent heavier weight birds from escaping. Light weight birds however are good 
flyers, and hard to keep inside a fence with-out a top. Last year we let one of our american game hens free range in the yard
while we were doing outside chores..we absolutely could not catch that bird. She'd roost high up in the tree tops. Heres a quick
tutorial here on BYC, and a helpful picture for helping you clip the wings. You want to clip the Primary flight feathers. 
Wishing you luck.
Rebecca
BYC wing clipping tutorial ~ CLICK HERE