Related Clues:

• Barnyard cry
• Chester White remark
• Sound on a 58-Across, perhaps
• Pen pal's protest?
• Swine sound
• Pig's sound
• Pigpen sound
• Swine squeal
• Sow's remark
• Reply to a pen pal?
• Pen word
• Pen parlance
• Piglet's comment
• "Sooey!" response
• Sound from Old McDonald's farm