Possible Clues:

• Recruits roll in from three directions
• Volunteers organise silent protests at the end
• Joins the military
• If one listens one may join forces with this
• The way one listens to the way one joins up
• The fowl has lost her head, leans to one side and joins forces
• One will be 10 across if one does this
• Joins up, taking quarters overlooking field of combat
• Listens out for recruits
• Joins up so as to be silent about the South