Could you post some pictures of her lying down and trying to move so we can see what position she’s putting her legs in?
Marek's is unlikely, there isn’t clear information about wether geese can catch the virus or not but from everything I’ve read it’s probably highly unlikely.
Botulism is questionable, it’s possible but unless she’s been exposed to stagnant water or something rotting in the one day she’s been alive I doubt it’s botulism.
Niacin, thiamine, vitamin E, calcium, protein deficiencies among other nutrient deficiencies are a strong possibility, sometimes if the mom was deficient the babies can be born with deficiencies so I would get her a multi-vitamin supplement, something like rooster booster poultry drench along with some probiotics to help keep her immune system working it’s best. You can use an eye dropper to drip it down her throat, which might be tricky as she’s so small, you can also put it into her water which would be safer.
Temperature fluctuations while incubating can cause birth defects and neurological issues.
There are other viruses/ bacterias that can cause neurological diseases but it’s hard to narrow down which.
Another possibility is slipped tendons which can be corrected if caught early.
