Baby goats disappear in broad daylight.

I'm so pissed right now. And I'm sorry if this post sounds like a vent about my issue. This happens at least once everytime my goats kid. I just had two kids (twins) disappear in the middle of the day. I left at 12:30 and typically come back at 3:00 to check on the mom's and kids again but I had a terrible migraine, and my goats pasture is on the opposite end of the road of my house so I have to drive to get to them and didn't want to try driving while the room was spinning. So I come at 2 hours later than usual at 5:00 to a mother goat screaming her lungs out and her twins missing. No sign of anything, no struggle, no bodies, nothing. This happens EVERY year and I'm so tired of it happening, they have a five foot electric fence surrounding the pasture but obviously that isn't stopping something from getting in. The giant carport/overhang thing that the herd sleeps under and the kids stay in 24/7 at this age, is right beside two RVs that some people beside the entrance of the pasture live in yet some predator still has the balls to show up in the middle of the day with humans living nearby. I also searched for tracks around the area and could find nothing.

The main question I have here is what predator will come and grab a few kids in the daytime with humans frequently nearby? And also leave no trance each time? And how should I catch or combat this predator?

I don't have a barn I can lock the goats up in or stalls, so I feel kinda helpless about being able to just physically put them somewhere safe from something breaking in. They just have a large carport like structure they take shelter in, there's also three cattle hutches with no door and one goat igloo. I'm going to put all the remaining kids (14) in a few of the large cattle hutches and build some kind of makeshift door onto it to keep them secure, and only letting the kids out when I'm there to supervise because I really don't know what else to do to stop something from getting to them. I'm down there most of the day usually (and a few hours at night), because I worry about making sure all of the young kids are safe. All that I feel I can do is sit on guard most of the day, and lock the kids up when I'm not there.

UPDATE: The twins were found at the back of the pasture squeezed in between some old rusted giant metal poles and are alive! Thanks for everyone's advice!