Abstract: The laboratory of the early universe provides a setting for testing Beyond Standard Model (BSM) physics in the particle and cosmological sectors. Any BSM physics in operation at early times may produce slight deviations on the primordial element abundances and cosmic microwave background observables predicted within the standard cosmology. The identification and characterization of such BSM signatures require a precise treatment of the neutrino energy and flavor wave functions during the time of Big Bang Nucleosynthesis (BBN) using the Quantum Kinetic Equations (QKEs). I will review some of the work done on characterizing BBN with a Boltzmann-energy-transport approach, as well as ongoing work towards a full QKE treatment with neutrino oscillations and collisions. A QKE treatment of early-universe neutrino physics will greatly assist observers and theorists as the next generation cosmological experiments come on line in the near future.