posted 11 years ago
Welcome to permies David.
When you say 'so called organic', what do you mean?
If it is truly organic, the hens should never be fed antibiotics, chemicals, GMOs, etc.
If the label just says something like 'Natural', 'Nature's own', etc. then it probably will contain trace amounts of those additives. If it actually says "Organic", and/or has an OMRI label, then it should be safe to use.
If it does however, have any of those ingredients, probably the most concerning would be the antibiotics ("against life").
We live in an over medicated society, and tests of treated waste water often reveal substantial quantities of antibiotics. Besides killing much of your soil life, their abundance in 'the wild' (your lawn and dog) is a primary factor of the evolution of disease organisms that are developing immunity to these 'life savers'.
EDITED to add: This is much more of a concern on edible crops than it is on a lawn, but still a concern.