If used with walking, a collar can absolutely make a trachea collapse. Franklin wears a collar when I'm home (and supervising) for ID in case he were to slip out the door. When he's in his playpen, I take it off because there is no chance of him escaping and there is the chance that he catch it on something and hang himself.
When walking, you should ALWAYS use a harness to reduce pressure put on the trachea. |