  There is no direct evidence for radiation domination prior to big-bang
nucleosynthesis, and so it is useful to consider how constraints to
thermally-produced axions change in non-standard thermal histories. In the
low-temperature-reheating scenario, radiation domination begins at temperatures
as low as 1 MeV, and is preceded by significant entropy generation. Axion
abundances are then suppressed, and cosmological limits to axions are
significantly loosened. In a kination scenario, a more modest change to axion
constraints occurs. Future possible constraints to axions and low-temperature
reheating are discussed.
