D S,s advice on the lambs breast seems sound,plenty of fat in lamb ,I would doubt the dog was wormy ,that usually increases their appetite,Ive the opposite problem,Ive a year old beddiex collie xwhippet ,kept for bunnies,he will eat any thing ,and stands next to me when Im peeling spuds hoping a bit of peel misses the bin,he isnt wormy ,but demolishes fruit,lettuce,celery,any vet pill such as Amoxycillin,or Rimadyl as though they were sweets,he caught a dove in the garden recently and retreived it to the back door for me,as it was shut he ate it feathers and all.