  Twin Higgs models solve the little hierarchy problem without introducing new
colored particles, however they are often in tension with measurements of the
radiation density at late times. Here we explore viable cosmological histories
for Twin Higgs models. In particular, we show that mixing between the SM and
twin neutrinos can thermalize the two sectors below the twin QCD phase
transition, significantly reducing the twin sector's contribution to the
radiation density. The requisite twin neutrino masses of order 1-20 GeV and
mixing angle with SM neutrinos of 10^{-3} - 10^{-5} can be probed in a variety
of current and planned experiments. We further find that these parameters can
be naturally accessed in a warped UV completion, where the neutrino sector can
also generate the Z2-breaking Higgs mass term needed to produce the hierarchy
between the symmetry breaking scales f and v.
