well sorry to hear this, next there are a few guys on here that have tracking dogs, I would try to find one, a dog is a great tool of you can get one
as for meat going bad, well there hide works both ways to protect against heat and cold, so in 70 degree's, I would say it could last several hrs after its DEAD, I say dead, as it could be still alive for many hrs , from being shot, or days before a SO SO hit actually kills them,
I would judge how stiff it is once found, they get stiff in a few hrs and well, how bloated it is, and then HOW it smells when you open it up
they will boat a lot faster in HOT/warmer weather
best of luck to you