I agree with with
kaykay's comments.
I am so sorry that you had an angel foal...
320 days is prime foaling time around here!
In the past, I have had to pull a couple of foals who had a leg back - as there was no room (or time) to reposition... and they (and mom) were just fine.
The cord could have twisted in the final moments... and there is nothing you could have done to prevent it.
We had a normal foaling here last year - all was well, easy delivery, experienced mare, no complications - and yet that filly never took a breath. Despite extensive resuscitation attempts that have rarely failed me in the past. Sometimes - it is just not meant to be.
Equally - I have had mares lay on their backs and push. Roll. Get up. Roll. etc. - all sorts of rather interesting gymnastics to position that baby. And even that does not do the trick at times!
As was mentioned earlier - and it bears repeating for anyone new to foaling out, even when the term mouth to mouth is used to describe resuscitation - it is actually
mouth to nose. Make sure the fluid is cleared out of the baby's nose. Baby is laying flat... hold its mouth closed and pinch the nostril on the down side closed as well. Blow into the nostril on the upside... observing the baby's side to see if you are blowing enough to inflate his lungs... you can do gentle compressions over his heart if he does not seem to have a pulse.
Other techniques to stimulate babies who may be slow to respond... tickle the inside of a nostril with a piece of straw - the normal reaction is to sneeze. Pinch a tongue to get a reaction. Or an ear. Rub him down vigorously. Stimulate in any way you can. I use my fingers to do a wiggly rake down the baby's topline from ears to tail. One last ditch All Else Has Failed No Options Left effort - that I saw work a few times on the Thoroughbred farm I worked at - is to pick the foal up - and DROP HIM. Flat on his side. From about a foot and a half - two feet in the air onto a cushion of straw/bedding... that served as a shock to the system - and sometimes a baby that we were about to give up on was brought back to sputtering life. Again -
that is only the final option.
Foaling can be the best of times.... and the worst of times.