Goose poop - why is it so tasty to a dog?

I posted this over on another board a couple of weeks ago and got one response (good advice, but always open for more) so I'm hoping for some more input.

Just a little background - This is my third Lab pup, now 19 weeks old. My first was not a hunting dog, had little retrieving desire, and was a great pet for 15 years. I did get her to be a good upland dog, she would handle some, and retrieve anything that had feathers. Otherwise, fetch was not in her. My second was a great little FT pup that was only with us for a few weeks last summer from the age of 12 to 18 weeks. Amazing little dog with incredible desire, had her running doubles, playing baseball, simple blinds, and 100 yd singles under control at that young age. Show her once and she got it. Unfortunately, she had a cancer tumor and went back to the breeder. And then there is this one out of FT and HT background. At 19 weeks she has "forgotten" everything from obedience training I've given her since 9 weeks and it coincides with the spring time emergence of animal droppings. So here goes:

One problem with living in the perfect spot to raise a retriever is having up to 100 geese on your front lawn from April to November. They're out on the ice right now and will be on the lawn as soon as the snow melts. Any suggestions on how to prevent pup from eating the tootsie rolls they leave behind? Is this something an e-collar would help? I plan to get a collar later and get some help in the proper use, but wonder if this might be a case for getting it now. Pup is only 4 months old right now, so probably too early? She certainly knows "No!", but also knows the value of putting distance between us to get away with non-compliance. The same yard full of goose poop is also the yard and beach where we train, so getting this through her head is a big deal for me. I'm not a vet, but I can't imagine eating goose droppings is good for a dog and it sure doesn't make you want a kiss!

Any suggestions are appreciated.