FIP is a vile despicable killer and it rears its head most often in places where the animals are mixed together and are not in good conditions.
As far as I know from various discussions about FIP, if a cat gets it, it will die painfully.; if its wet then it will die quicker than if it it is dry.
Its very hard to diagnose unless the cat is dead,
There is a Dr in Scotland who is the expert on FIP in the UK, Dr Kate Addie and she used to have a very knowledgeable website which we had a link to but it went down and dont know if it has reappeared. Off to check!
This is the link and now has loads of othe stuff about cat flu etchttp://www.dr-addie.com/WhatIsFIP.htm
I would say that this shelter should isolate all sick cats until they know what is wrong with them and any suspected of having FIP probably should be probably be PTS to save them a terrible death in agony because it appears to go for a while often but then comes back even worse and there is no cure
They should stop rehoming until they have all well cats and also should not take any in.
Any shelter should ensure they are not rehoming animals with somerthing like FIP or they are not caring for their cats.
In this country one would be able to ask RSPCA to inspect under the Animal Act and suspect threy would take the easy option if loads of cats had FIP and they would just PTS all cats
If they are letting cats die due to FIP this is cruel in the extreme, is their no way of any local law or body that could get involved in this?
Some cats are more susceptable to FIP than others and this is in the link.