I have an ankheg head that weighs a ton. What good is it?
The smith in Beregost will only make one set of ankheg armour, and it takes some time (he’s usually late). There are a few other people who will buy them (careful; they rot) but for their weight they’re hardly worth it by the time your party is capable of killing an ankheg to begin with. There are also good arguments that full plate is better than ankheg plate; for me it depends on the ST of the wearer. Full plate is very heavy and if the wearer doesn’t have high ST the AC benefits of full plate are balanced by the reduced carrying ability. In TSC ankheg armour is a major improvement for druids.