Legislation advancing in both chambers of the Maryland General Assembly could make all chicken raised in Maryland free from antibiotics.  The Senate and House of Delegates separately on Monday passed bills forbidding chicken companies from routinely giving birds antibiotics used to treat humans, unless the animals are sick.

The measure follows concerns about the widespread use of antibiotics in livestock, and whether it erodes the medicines’ effectiveness in humans. Already, Maryland’s largest poultry producer, Perdue, voluntarily stopped using those medications and advertises its poultry as antibiotic-free. Several large food companies, including McDonald’s and Panera, also pledged to only serve chicken that has not been treated with antibiotics.

The versions passed 139-1 by the House and 35-12 by the Senate differ in reporting requirements for times antibiotics would help a sick bird. Lawmakers have three weeks remaining in the annual General Assembly session to reconcile the differences and seek the governor’s signature.