Help Ronald the Cockerals crow has started to sound like one of those party blowers, that role out l

Hi all...In need of advice...my black wyandotte cockerel who is about 18 months old, has always been a noisy so & so with a top crow..my how I have gotten used to it blasting out each morning.....However over the past few weeks his crowing has almost stopped & when he does crow it sounds like one of those lizard tongue party blowers (you know the ones which we often blow so that the paper unrolls into somebodys ear)...

His plumage is nice & shiny has it always has been... he's eating ok..I have just started worming him...but although he is active he doesnt quite seem his old dominant self (each morning he used to chase all the hens around before eating his breakfast, now he just eats his breakfast & wanders around)...

Any ideas?
Zeb