Wheezy cockerel?!!?

My Light Sussex cockerel sounds wheezy as though his chest is bad. He is approx 24 weeks old. However, I did hear him crowing like mad for the very first time today!       Proper crowing not the strangulated noises he made whilst he's been practicing. I have checked him over, I'm not experienced with poultry but he seems fine otherwise. No runny/foamy eyes or nose, upright and red comb etc. Might this be to do with him crowing or should I be concerned. :cry:  :cry:  :cry:

Drat!!!!!!! :shock:  :shock:  :roll:  :roll:

I am going to have to catch him again to  smell round his mouth. Still I am learning.