Heard you lost your birds, I'm truly sorry about that, it's amazing how attached you can get to a noisy pile of feathers with beady eyes.
Not to sound hard but now it's time to go to work and be a CSI! Take a few photos and notes of the carnage, there are many signs left by the guilty party. Look at the birds, is just the head off? Where have they been eaten on? Walk, better hands and knees crawl around your containment area and look for tracks and points of entry. Compare your findings with the threads on this site and ask questions.
Once you figure out what did it, trap or kill them! Most predators will return to the scene to eat or see if they missed anything. In their mind, it was a easy meal and they will remember it and return.
Fix your pen! Chicken wire will hold birds but won't stop a determined predator nor will sloppy construction. Use your oposable thumb to win!
Once this is done, do your research and find a new exciting bird you want to raise and get them, It's like getting your heart broke, get back on the horse and fall in love again! Unfortunatly we have all lost birds and dealt with it in our way and we still have birds for our own reasons. Mine is stress relief /entertainment, nothing like pulling up and stepping out of the truck and getting mobbed by a flock of chickens who only want you for your chunks of fruit & bread or watching turkey chicks climb a plastic pallet and "grind" their way back down the skid. Right now I have 6 spoiled hens standing in my garage waiting for me to come out with a treat for them. It's magic how the stress melts away
Yes, I'll pop there heads off this fall and butcher them but for the summer they will be guarded, they will have a fenced in acre to grow up in and sneak thru, a dog that guards them like they're puppies and a couple humans who truly spoil and enjoy them, their life is good and so is ours thanks to them