Hi everyone, first time posting. I received an HM for the predoc award last year and requested feedback right away. I never got a direct reply to my email request (saying that they got the email, etc.), but I did end up receiving a link to the feedback on my application around mid-June. In other words, you may have to be patient. The feedback was actually more detailed than I expected it to be and was pretty helpful when I reapplied this year (ended up as an alternate, so a slight bump up! Fingers crossed that someone declines...).
I hope that's helpful!