Just got back from the vet who confirmed that my GCC's recent vomiting, temporary anorexia + drinking excess water and poop blockage problem, as well as the long-term yeast colonisation of her crop, was, as I suspected, due to FIBRE INGESTION
Most of what you hear about fabric/rope toys being unsafe relates to fraying/entanglement, which is why you'll still see supreme cotton and fleece being sold as 'safe'. Unfortunately, parrot stores for some reason completely ignore the ingestion side of things - where the tiny fibres cause a blockage in the digestive tract and can well lead to the death of the bird. Our vet
told us that most of the time, this is diagnosed as the cause of the issue only on autopsy, because the bird can be ok while the fibres are building up, then death can come swiftly once the blockage is complete!
Even if you don't think your bird is chewing on something, be careful. I've never seen Shark chew on her rope perch, it's barely fluffed up just from her walking on it for a year - and yet today the vet found colourful fibres in her crop. This is the only colourful fibre product she has access to, so it's a no-brainer - the rope boing will have to go!
The veterinary profession knows this is a problem, just like zinc and split metal on toys, so why is it listed nowhere else that I've seen? I would personally consider any toy manufacturer claiming that a rope or fabric toy is 'safe' to be either negligent or misleading