
My vet told me the temperature can vary quite a bit up and down in the last few days it is when you get the big drop that stays dropped it will be within the next 24 hours.
Having said that, we didn't really get the big drop with Pippa, it went steadily down then rose a bit a few hours before she had them
Don't suppose that helps much really but I guess everyone's dogs are individual.
Good luck with your foster dog and well done!