First, don't forget -- it's your label! This is a chance to tell your customer what's special about your product. At the same time, you do have to follow some basic rules.
Your label is required by law to have some basic information: product name, inspection legend & processing establishment number, handling statement, net weight statement, ingredients statement, address line, nutrition facts, and safe handling instructions. All of these must be on specified areas of the label, prominent, conspicuous and able to be read & understood by the buyer.
Any additional claims you want to make about your product -- e.g. grass-fed, organic, no antibiotics administered -- will require proof that they are true. For organic, you'll submit a copy of your certification document. For label claims like no antibiotics administered, you will sign an affidavit to submit for approval.
For federally inspected meat and poultry establishments, all meat labels must be approved by the Labeling and Policy Division of the Food Safety and Inspection Service (FSIS) in Washington, DC.
If you use a state-inspected processor, your labels must be approved by your state's meat inspection program. You may want to ask your processor's inspector the exact requirements.
This website, from CSU & UC Cooperative Extension, is a great guide to the label process, though it focuses on federal approvals: http://www.csuchico.edu/agr/grassfedbeef/label/index.html
This USDA website is also useful: http://www.fsis.usda.gov/regulations_&_policies/claims_guidance/index.asp
If you want the whole, 100+ page pdf "A Guide to Federal Labeling Requirements for Meat and Poultry Products":
http://www.fsis.usda.gov/PDF/Labeling_Requirements_Guide.pdf
