  Exciting clues to isotropic cosmic birefringence have recently been detected
in the $EB$ cross-power spectra of the polarization data of the cosmic
microwave background (CMB). Early Dark Energy (EDE) models with a pseudoscalar
field coupled to photons via a Chern-Simons term can be used to explain this
phenomenon, and can also potentially be used to simultaneously resolve the
$H_0$ tension. In this work we incorporate an early dark energy scalar field,
including a Chern-Simons coupling, into an existing Boltzmann solver and
numerically recover the $EB$ cross-power spectrum for two models in the
literature; the $\alpha$-attractor, and the Rock `n' Roll field. We find that
both the models fit the $EB$ spectra, and the $EB$ spectra alone do not possess
sufficient constraining power to distinguish the two models based on current
data.
