Happens all the time. My D.I.L. who has two horsed reported two horses in a field near us that were very badly neglected. The case was so bad that the horses were signed over and removed within a couple of days. After seeng a Vet one was put down, the other which was full of worms and could hardly walk as it's hooves were so overgrown, was brought back to health and eventually re-homed. This all done through a Charity Organisation.
Calling out a Vet to a horse will always be around £100.00. just to get them out is a basic £25.00 before any treatment. People do not realise how expensive it is to have a horse. Horses need injections, hooves trimming, shoeing. Then they need hay and horse food, bedding for the stable when the weather is bad. The list goes on it's around £2.000 per year to keep a horse.
I was speaking to a friend yesterday who had been at a local livestock auction centre There was a horse sale and the horses were making as little as £5.00 each, the sad thing is this means they go for horse meat. Apparently even a thoroughbred well worth over £2,000 only made £200 and one poor horse could not even get a bid.