My experience with flying two dogs (separately, two trips) from Tahiti to Phoenix (MOZ-PPT-LAX-PHX), although NOT on Delta, is that the luggage/cargo employees are not allowed to open the crate to walk or comfort the dogs. Their liability in the event the dogs escape is just too great... In my case, it was apparent that my dogs were not even given the extra food I provided (in a top compartment) or additional water into the crate container cup.

If making a trip like that again, you might consider including an overnight layover in a dog-friendly hotel along the way to give the dogs a break along the way. I know it complicates the itinerary, but sometimes it makes the trip easier.

What you went through is a NIGHTMARE that should never have happened! I'm glad you were safely reunited with your dogs!