Related Clues:

• Sound from a snout
• 'Old MacDonald' sound
• Pen emanation
• Sound from the pen
• Heard from a pig and a duck, it's in the pen
• Stifled laugh
• "Babe" sound effect
• Porcine cry
• Cry from a sty
• Comment from Porky
• Advice from 96-Across?
• Advice from 23-Across?
• Swinish comment
• Ms Piggy pronouncement
• Sound indignant