Here is the stickler and something to keep in mind. If it's cut and laying and it gets rained on and it gets hot and humid the following day, flip it right away or ted it out. Reason is, the forage will heat up with the moisture and will get rank underneath.
If my hay gets rained on, I'm out there as soon as the dew is off, the next say, blowing it out or flipping it, depending on how wet it is and the heat and RH.
I use an IR thermometer to check the temperature of the forage near the ground and if the temperature is more than 5 degrees above ambient, I get with the program right away.
I only bale very high quality alfalfa hay for contract customers and they want prime material and pay for it, so I'm real cognizant of what the forage is doing all the time.
It's babysitting for a fee, sort of.
you mix a little science with some common sense and a healthy respect for Mother Nature and usually you can come out smelling like a rose. I've never had to rake off a field to the ditch or burn rank forage.