Long story but I went with my family to a sanctuary on Saturday to take part in a feeding experience.
A couple of things concerned me though, 1 of the rabbits didn't seem to have a water bottle in its cage (most of the rabbits were free ranging). I asked and the guy said 'oh its in the other barn' - not quite sure how that was going to help the rabbit but still. Then my children were holding some of the young animals and I was making sure they were being really careful, one animal moved and my dd nearly dropped it, i had my hands under to ensure she didn't and the guy said 'oh don't worry they've fallen from higher than that before' 
I saw a free roaming rabbit that was really tame, didn't even move when I stroked it. I noticed fur missing under its chin, I picked the rabbit up and took it to the man working there. He said the rabbit had had a litter and had pulled the fur from its chest to line the nest. He did say the rabbit had had antibiotics but wasn't on them now and didn't need anymore.
I held the rabbit for ages, fell in love with it and half jokingly said 'do you rehome?' He said yes and I said we'd love to take the rabbit home (have cage, run, all suitable stuff, my dd's two rabbits died two months ago). I was a bit shocked that he didn't ask me for address, phone, do a home visit etc. End result - paid donation, took rabbit home.
Get home and realise rabbit is ridiculously thin. Take straight to vets - the fur missing under chin isn't from nest lining but a nearly golf ball sized abscess from a tooth infection. Rabbit is weighed and is less than half the weight it should be.
Hand feeding rabbit now, booked in for teeth/mouth check under sedation early in week. Vet says rabbit may not survive. Very sad. We will pay all the vet fees and I will give the rabbit a loving home if she pulls through (crossed fingers)
So, I ummhed and ahhed and phoned the RSPCA to report the sanctuary. I feel really bad, on the one hand, because it is a sanctuary but on the other hand surely this is terrible neglect? The rabbit must be in considerable pain and would have died if I hadn't seen it and taken it home. There were several other rabbits there that looked 'manky' not good phrase but they didn't look in top form, the other animals all seemed fine.
What would you have done? Should I have told the RSPCA or not?