Related Clues:

• Grunt, having nothing to write with?
• Pig's greeting
• Pig’s grunt
• Truffle hunter's squeal
• (I'm a pig!)
• Sound from a pigpen
• Sound of animal coming from Fido in kennel
• 'Heroin kept inside' heard from pen inmate?
• Bit of pig speak
• Pig's "hello"
• Sty greeting
• Sound that 40-Across make
• Porcine noise
• [I'm a pig!]