My 7 week old puppy is tarting to eat her own poo why and how can I stop it

Believe me-- it's more normal than you think it is. We have dogs that like to sniff around the cat litter boxes and take 'treats' from it-- we have no idea why they find it so appetizing.

A lot of animals have this behavior-- and it's pretty disgusting, I agree, but it is normal.

If you're curious, try reading this article:
http://www.cvm.uiuc.edu/petcolumns/showarticle.cfm?id=166

Many puppies do it, and some outgrow it. Unless you are fighting worms, usually it hurts the owners' peace of mind more that the dog. Cleaning them up before the dog gets to them is the best solution. Adding pineapple juice or canned pumpkin or the commercial products Forbid or Deter work with some dogs.