Sick chick? Snoring and coughing?!

[DrFarmersDrWife]

I have my second set of chicks and one of them is making a coughing kind of sound and a deeper sounding chirp at times. When she sleeps she kind of sounds like she is snoring. Is this a normal thing for some chicks? She is the biggest and most rambunctious. I mean she was jumping up on a three inch tall box. The are 6 days old.

Thanks in advance for any advice!!