, I don't think I'm going to be much use to you except to say this is a very difficult sort of situation, and I empathise. If you've got an even passing acquaintance with the animals, it's even harder to forget about them and their problems, than it is with even knowing that there are so many domesticated animals living in terrible circumstances - both farm animals and pets. This is something I have found distressing since I was a little girl, and it seems you feel that way too.
I think this sort of situation should
be handled by animal welfare organisations like the RSPCA enforcing the law, but unfortunately, at least in Australia, they often don't. Over here, my husband and I have made several RSPCA reports and it fell on such deaf ears, and also in the experience of other friends with similar scenarios, that we decided long since it's a waste of time even to try them, where we live.
The first case we reported, more than ten years ago, was a paddock full of newborn dairy poddies (they get taken off their mothers, and put in paddocks together) near a farmhouse who had been left without any form of shelter despite a clarion-clear severe weather warning that was issued to that part of the state. We chanced upon the situation hiking with a friend. Half the poddies had died of hypothermia - about half a dozen or so - several others were in the process of dying, and the rest were a sorry, shivering lot, penned into a little square of grass with no structure or even hedge to shelter them. It was completely appalling. The farmhouse was 50 metres away and there were people in it, about 10 in the morning after the hailstorm, and a freezing wind still blowing. The RSPCA told us, when we rang them, that they don't get involved with livestock. (And yet we read in the newspaper soon after that an RSPCA officer had gone to investigate the report of a plastic bag full of live garden snails dumped at the local tip, and attempted to set them free.)
The next was an old horse at an agistment place I had a horse at - after half a year of watching this very underweight old horse salivate every time I fed my own horse, and get no extra feed from their owner, and no blanket in the fierce winter rainstorms in this part of the world - I often found him in the paddock wet through and shivering when my own old mare was snug in her blanket - I simply couldn't bear it anymore, and chatted to the RSPCA. They sent a vet out, and the vet simply said, "This is just an old horse and old horses get skinny." End of. What can you do?
There was one other situation involving a dog who was being kicked and beaten by his owner. This was something a neighbour had witnessed and was really distraught about, but he didn't want to report it to the RSPCA. We had seen the dog owner viciously kick his livestock, so it wasn't out of character, plus the dog was now skinny and roaming the countryside trying to scrounge food from other local farm dogs' bowls, afraid to go home. The neighbour who was telling us this stuff told us that the dog had shown up at another neighbour's place he was visiting, and his owner had come looking for him, and the dog, which had been friendly with the people present, immediately raced off on recognising the car. We knew the dog was roaming the countryside, we had seen the owner abuse other animals, and had heard what neighbours were saying about it, but the RSPCA refused to act based on our report because we hadn't personally seen the person kick his dog - never mind that we had
seen the distressed, skinny dog running around, and had
seen him kick other animals. That's the last time we've ever called the RSPCA. We did call the ranger, and tell him what we knew, and he also knew the track record of the dog owner, and said he'd try to catch the dog and put him in the pound. That was a bit more useful.
Where we live, last winter we saw three adult cattle die of exposure due to being in poor condition and not getting any supplementary hay, next door. The whole herd in that paddock was skinny and weak and spent a lot of time lying down as the winter feed gap opened up. It was pointless trying to call the RSPCA. Because their carcasses were left to rot in the paddock by the road unattended, and the smell drifted over to us, we rang public health, who took that very seriously (and we also reported the cattle deaths to the Department of Agriculture in case of communicable diseases - they came and tested the carcasses and rules out communicable diseases for all the neighbourhood, it was simply death from neglect). So what we basically could effect is that if our neighbours have animals dying from neglect at their place, they are obliged to drag them sufficiently far away from the road so that passers-by can't smell them. However, they can continue to neglect their animals, and they do. The same paddock is once again filled with skinny, weak animals, who are already suffering. It's really frustrating - just like the situation you're in.
All I can say is that animal welfare deserves more attention from the authorities than it's getting. Welfare laws exist, but get broken all the time, and generally, the only time the RSPCA in our area seems to do something about it is if it's beaten-up dogs with next-door neighbours who've witnessed it complaining, or starving cats, or something else worthy of their Australian TV programme (like a kitten stuck up a tree); or unattended animals with overgrown hooves or broken limbs or otherwise needing to be put out of their misery, and it's not too far out of their way to drive.
If it's better where you are, then you could try an animal welfare organisation. Getting personally involved, going it alone, is going to be really stressful for you, and you can make so little difference to their situation, plus this is going to be an ongoing issue unless the powers that be are actually interested in enforcing animal welfare laws.
One alternative approach might be to take photographs / footage if the animals get distressed / hyperthermic / run out of water / etc, and then to bother the RSPCA with that footage. But again, you're leaving yourself open to some potentially nasty repercussions from people that really sound like the sort you'd want to stay well clear of.
Good luck with it...