Can you tell us why you think this might be botulism and not weakness from another bacterial infection? Or even dehydration? Or possibly a broken egg within her?
For example, has she had access to any of the following:
A compost pile, kitchen scraps, discarded food/feed
Wet/soured feed or mildew
maggots (even in decaying woods)
fermented berries/fruit or anything over-ripe
meat or milk products
any toxic plants
Algea water/stagnant water/ponds
If she can pick her head up, I'd not put botulism on the top of the list as a bird with a limp neck and botulism at that point can't pick up their head. The flush can often kill a bird who doesn't have botulism. So it's very very important to literally remember that you may kill your bird by using a flush. Do pull the feathers - if they come out easily then it IS botulism but the lack of that symptom doesn't rule out botulism either.
If you use one, I'd highly recommend doing it the way MSUcares recommends:
http://msucares.com/poultry/diseases/solutions.html
http://msucares.com/poultry/diseases/disbact.htm
I'd like to see a broken egg within her ruled out. Would you say that the yellow droppings could at all be yolk?
I'd also want to see avian monocytosis ruled out as she's of that age and sometimes white chalky droppings (and possibly passing yolk) are symptoms. Incidentally this was a name for a nonspecific illness that has now mostly been ruled to be other things, but at the time it was treated with molasses (likely to flush out bad bacteria and toxins).
So if you do it just know the risks.
You will also want to put her up seperate because IF this is botulism (well any toxin producing bacteria) then you want to throw each and every dropping away quickly and keep everyone away from the bird. Wash your hands thoroughly. You will not treat for more than four hours as it would completely deplete the bird (if it won't in less than that time). You will then need to really push probiotics preferably not yogurt strictly. I would really recommend acidophilius capsules or Probios brand powder instead if you can. But at LEAST use yogurt. You must. You must replace good bacteria as you're flushing them out, leaving a completely vulnerable gut particularly vulnerable to opportunistic bacteria and yeast.
