I don't think it is so much that pig bones are absent from colonial
contexts, I think that they are there, but in much lower quantities than what
is seen in both archaeological and documentary sources on more recent (i.e.
post 1800) sites in the U.S. South.  Off the top of my head, I recall
beef-mutton-pork remains are fairly even in the big samples available from
18th-C. Chesapeake sites, with beef a little, or a lot ahead in particular
cases, but here at the Hermitage for strictly 19th C. contexts the MNI ratio
of Pork:Beef:Mutton is close to 8:1:1.  I think (and other archaeologists and
historians listening in are invited to add their takes) that the transition
to pork reflects the fact that it yields a big return for little investment,
it preserves easily and pretty palatably, and it tastes pretty good
(especially barbecued, with a little spicy sauce, and a corn cake on the
side).  It just seems to have taken southerners about a century to figure
this all out.
     Gotta go.  Late for lunch.
                    Larry