Possible Clues:

• Problem about bird: where to attach its flight muscles
• Serious hesitation kept close to one¿s chest perhaps
• Problem about seabird's breastbone
• Total absorption of bird's bone
• Serious pause at what's in the chest
• Being so unyielding, you get grand in the breast
• Additional problem eating bird - a big bone
• Bone in rear? Sound doubtful
• Rib connection
• Munster (anag.)