Piglet mortality

I've read that it's normal to expect a 20% mortality rate raising piglets, with the first 3 days being the most critical.  I'm at 25%.  Today the 3rd piglet died but I don't know why.  Yesterday one was crushed by Roxie but today's little guy just seemed sick.  I removed it from the others in case what it had was contagious.   The others were all very rambunctious this morning but tonight it's 100 degrees and they're all lying spread apart on the mud Roxie delivered to them.  She's lying in her mud hole.  I don't know if the heat is too much for piglets or not.  I sprayed Roxie with the hose and she stood there and relished in it.  I was tempted to spray the babies but didn't think it was a good idea at this young  age.  The little piggies are covered in mud and look nothing like the picture I posted last.  The one that died today was the cute black and white belted boy.  He was a pretty little thing. 

I'm trying to decide what my plan is for pig raising.  Should I keep Roxie?  Should I keep a baby or two for the freezer?  Should I raise a boar to breed my own or should I get out of pigs altogether?  I'm going to wait and first see how the rest of the babies do before I make any decisions. 

One more day of really hot weather and then it cools down to the 80s and even 70s.  I think all our animals will be happier with the cooler weather.