Pieces of thread from clothing or rags cans get into the chickens yard, and chickens will peck anything and eat it. Here is a recent thread on here to illustrate (just need to read post #1)...
Please keep checking daily for a string or thread around the tongue perhaps way down where it is hard to see. Maybe even visit the vet. Someone on here recently treated their chick for along time only to find a thread that had done major damage. They had checked before. Apparenty this a...