What happened to spears?

[TinCow]

I have noticed a similar thing in my campaign, but I do not think it has anything to do with spears. The only spear units I have access to (playing as England, about 70 turns in) are poor quality spear militia and levy spears. These guys have pretty low stats and I suspect that is why they are being destroyed. I have had some rather unpleasant encounters with Flemish Pikes and some Scottish pike-ish unit whose name I cannot recall. In comparison, I picked up some Crusader Sergeants along the road to Antioch and they are extremely good, with a high defense rating. Unfortunately I cannot recruit them normally.