This is a slightly different variation on an earlier question:
In the very early universe, the hot plasma consisted of fixed amount of radiation (photons and neutrinos) and matter (electrons, protons, neutrons, etc). There were many competing reaction taking place and using statistical methods I understand that you can deduce the particle content of the universe when radiation and particles began to condense into nucleons (at roughly 100 Giga K).
Dark Matter interacts weakly with matter (this, as I understand it, is the basis behind the LUX experiment) as do neutrons. Neither Dark Matter nor neutrons interact with matter using electromagnetic forces. Neutrons appear to factor into several of the reactions in Big Bang Nucleosynthesis (BBN) yet Dark Matter is at least five times more abundant than neutrons. So why doesn't Dark Matter participate in the BBN reactions with roughly the same probability as neutrons?