I sympathize with your situation, it's very frustrating when you are faced with the unknown variable of what all can come onto your property to do harm. It's expensive to fix it too.
We just moved to the country, where roaming dogs are a normal thing. Our property isn't fenced yet, and so I have free ranged nothing and no one. I've been into chickens over 15 years now, and I know how this story goes. Until I have a fence to secure the area, the birds will have to make do with the pens until I can safely turn them loose. I miss SO BAD the days of walking out into the yard and hanging out with them while they went about their business in total freedom.
When we moved in there was a partial fence around the front of the house. So we closed that in to get the dogs and tiny pigs situated. The coop got a run. Now we're finishing out the big old barn to move the other birds into. Then that gets runs.
But then the next task is perimeter fencing, because I'm not dealing with the neighbors. I've met most of them now, and they all have a completely different mindset than we do. I'm not even giving any of those dogs who have already visited a chance to do damage. So far there has been repeated visits from across the road, so that side will also get a driveway gate. 3 dogs come over to harass our 3 German Shepherds, they're quick to alert us to trespassers. The visiting dogs live in small kennels or on chains and are let loose to run on occasion. They're typically called back home when the owners hear the barking nonsense. Then there was a male German Shepherd trotting down our driveway, scoping the place out. I stepped out and saw him, and he turned and gave a look of "What? Just passing through." and he went on his a way. A super sweet unneutered German Pointer has been by 4 times now, more interested in my girl dogs than my birds thankfully. 1 coyote cruised along the creek out back, looking over.
Had I opened up those coop doors and turned them loose for the day, I would have lost them all by now.
So we're doing 6ft privacy panels down the road frontage (now is a good time of year to contact your local big box hardware store and see if they have any weathered fence panels from prior years they want to sell cheap. They just need pressure washed to be good as new!) Then we'll do 4ft privacy fence around the front of the house, it seems people like to stop at the stop sign and make my dogs bark. That open line of sight is going away through fence and landscaping. Not dealing with it longer than I have to. Also installing a no-climb feature along the top, one of my girls seems to be experimenting with escape and we'll nip that right there too. She is perturbed at my ability to know what she's up to from inside the house. LOL
Along the creek/tree line on the other two sides we'll hide field fence in there. I don't want to ruin the pretty visual with a fence, but we do need a barrier since that's the wildlife side. Was thinking I'd leave the deer trail open so as not to encourage them to fence jump, routing around where I see their trails. I plan on a garden at some point, will need to fence that area with something taller.
Now if something insists upon coming through our defenses, then the gun may come out because that's a problem. But I can't shoot something that was able to walk right on in, or even get that upset, because it's not like they read no trespassing signs. Failure to secure my belongings is my own fault. I feel so exposed not having a perimeter fence! The only barrier is the welded wire run fence. I check often for prowlers. Cameras will be added too, to see the driveway, house, barn, and pens. I've noticed desperate people too. Thankfully my dogs don't abide by strangers. I caught one person trying to sweet talk my dogs from the other side of the fence, and they weren't having it. Dog stealing seems to be a thing too around this area too.
It's hard to collect for damages. It's hard to replace birds. It's hard to potentially lose them all in one day/night. I've had losses before, and the take-away I have is "Good fences make good neighbors", even if I have to pay to fence out critters who should have their own fence. It's my responsibility to protect what's mine. Another neighbor has a pile of dogs, big ones too. They have a great fence and there has been no issue. If only the others would do the same! Dogs get dumped off around here too, ownerless. They'll go where they can get to!