It takes 10 times as much snow to make the equivalent amount of water so horses can get water from snow. Orange or red urine is normal once on snow due to oxidizing effect. Water should be given to the ponies as impactions can occur when dehydrated.
I wouldnt feed them either. They will get bits of feed and hay left by the horses. Deer scavenge and will come around at night when people arent there to pick bits of grain and hay. I see lots of deer tracks around my hay storage barns.
The law is definitely on your friends side should the person loaning the horse sell it. If she does your friend is within her rights to take back her horse from who ever thinks they own it. I will be another matter entirely if the loan person sells the horse and does not tell the owner where...
Im pleased to hear that your friends youngster is feeling better now. You were a great help to you friend and sorry noone on here could help with diagnosis. I have had a great many youngsters but I havent before seen what you described. If you eventually find out what it is would you post it...
It is close run whether she is a saviour or a hoarder. She doesnt work and has no money to pay to keep the animals. Instead of donations, them both getting jobs would best help their finances.
£15 a month increase? If so that is less than £4 per week. OP do you think it illegal for petrol stations and supermarket to increase their prices without giving you a months notice? Your livery yard is a business the same.
Can you tell people when to come and do their horses? I wouldnt. The time they come isnt relevant so long as horses always have hay and water available and bed cleaned out once a day. Some people work antisocial hours or have other things to do.