Oklahoma law allows:
" Oklahoma producers of eggs selling ungraded eggs from their own flock production are exempt from this subarticle. Nothing in this subarticle shall prohibit the sale of eggs produced on the farm and sold direct to the consumer. Eggs sold under this section shall be produced by hens maintained on the farm from which the eggs are sold." Title 2, Chapter 1, Article 10.A of the Oklahoma State Statutes. So, a person can legally sell eggs raised on their own farm DIRECTLY to the consumer.
The sub-article referred to in the above quote is sub-article 10-77 "acts constituting violations of sub-article" which refers to licensed, commercial egg producers in the state of Oklahoma who sell to retail outlets like grocery stores. Since a person sells directly to the consumer when running a booth at a farmers market, I believe the "sold direct to the consumer" standard is met. If the person was selling to the farmers market who then sold to the public, the person would have to meet the requirements of sub-article 10-77.
From what I've found, there is nothing in Oklahoma State Statute that would require all the licenses etc... to sell at a farmers market. Those requirements appear to be requirements from the operators of the farmers market, not State Statute.