My 5 month old Welsh Harlequin drake bill has started to go dry and flaky over the last couple of days. Humphery is fed on a mix of wheat and Allen and Page duck breeder pellets (a high quality, organic feed). What could have caused this, and is there anything that I can do to help him, suck as applying Vaseline or coconut oil? I am showing him in a months time at the National Poultry Show so I'd like him to be in top condition.