Hi
My lb 12 weeks old has lots of phlegm on his chest that we can't seem to shift. He has been like this for about 6 weeks now and it comes and goes a few times a day. You can feel it rattling through his chest 
Any ideas how we can help bring it up? It sounds like he needs to cough or clear his throat but he's too little to know how to do this
He has had his heel prick test which came back normal, a chest x Ray (for other reasons) which didn't show anything sinister and he doesn't have a cough.
Thank you x