Possible Clues:

• So eggs may be items supermarket's giving away?
• For what sounds foul that is never 20 across
• Allowed to roam, as chickens
• Where 8 down is not, there's no charge for cooking the chicken, it seems
• There's no battery for this
• Having no batteries provided
• There's no need for a 20 across to run this
• So a clutch could be available, but not battery?
• Let the mountains loose, perhaps, with no battery
• It does not run on a battery