This warning is from a Facebook post. It highlights the risk of 'fiber globs' (cropoliths) developing over time. They can cause severe complications and even become fatal.
I've previously posted a warning on this topic at:While I was at the vet, the nurse showed me some of the impactions that had been cut out of birds' crops. All from rope and fabric toys including sisal and Seagrass fibres! How scary !!! She showed me some of the toys that were the culprits. Some of them had absolutely no obvious evidence of chewing! Some people gave their birds those dried skin/ meat dog toys that ended up killing the birds. she said the only truly safe "rope" was naturally tanned leather or stainless steel chain).
From: https://www.facebook.com/Itsaconures...731762/?type=1
http://www.preciselyparrots.com/show...ing-Cropoliths