My in-kid nannies (and goatlings) get a gradual increase of the following in the last 8 weeks prior to kidding:
Sugarbeet shreds (soaked and still warm - I am a softie)
Rolled oats
Dairy nuts and/or A&P all round goat mix (some prefer one over the other
)
some flaked maize if I think she needs it
also obviously hay and if they stop eating any kind of fruit/veg/toast they like.
I also divide the meals up into at least three, up to four in the last two weeks.
I had the opposite problem last spring - two GG's going down with Pregnancy toxaemia in the last two weeks before kidding, and I think it was because they had been a bit on the chubby side early on and it was a cold winter - so more food... so they never slimmed down enough.... and both produced quite big twins...
I was quite quick in drenching, and had to do the goatling for all of the last week (plus inject Calciject as she refused to get up). She was actually right as rain as soon as the kids were born and milked quite well. Propylene glycol (I get it from the vets) is wonderful stuff!
I would keep a bottle of PG ready plus Calciject (and/or Magniject for milk fever), and also maybe prepare to feed back some of her milk to her in the first few days after kidding.