Battle of Tukayyid: Tukayyid Boar Spiders

[Cache]

On page 108 of Battle of Tukayyid there are rules for a stampede of Tukayyid Boar Spiders. However, the rules appear incomplete when compared to the beefalo herd rules on page 91. Specifically, what is the quantity of Boar Spiders/herds on the field? Do they literally cover every hex of the  Attacker's side of the battlefield from start to turn three and then the entire battlefield in turns 4-5? The stampede ends in the initiative phase of turn five (covering the entire battlefield). Do non-stampeding Boar Spiders interfere with movement or LOS? Can the stampede restart?

[nckestrel]

" Do they literally cover every hex of the  Attacker's side of the battlefield from start to turn three and then the entire battlefield in turns 4-5?"
They affect every unit in that area, yes. The individual Tukayyid Boar Spiders are not tracked. They are an environmental effect, not units, rules-wise.  The stampede covers an area, has effects, and when the stampede is done, is no longer has any effects.
There's no non-stampeding Boar Spiders. Once the stampede is over, the boar spiders are gone. 
No, they can't restart.

[DarkISI]

To add a bit of background to it:
I decided to go with a variation of the earthquake rules from TacOps for them. Why? Because treating them as units would have been a lot of work put on the players. It would also have meant to provide a creature Record Sheet for them. Which you'd then have to print out around 100 times. I wanted this to be fun, not work.
I also made sure to point out the Tukayyid Boar Spider was almost completely wiped out, meaning the stampede really cannot restart under any circumstances. There are almost no Tukayyid Boar Spiders left, the fighting drove them close to extinction. Those few left will most certainly not be able to stampede.

[Cache]

Got it. Thank you both for the quick responses!