Rooster Can't Crow

[softspot4silkys]

My 5 month rooster can't crow. He strains trying to crow but no sound comes out. Any suggestions on what to do?

 

[Frizzlett]

My Silkie rooster did that and then 3 days later, he let out his very first and loud crow. Give him time. He still does it sometimes too before he actually crows a few minutes later.