Our gorgeous Muscovy duck has had her first 4 ducklings hatch in the last 24 hours with only 2 remaining that haven't pipped. Both were alive a couple of days ago, which is when they started to develop dark blotches on the air sack end of the egg. Today I can't hear/feel any movement in one but can in the other. Assuming one has died but the other seems to be alive still. Wondering if I should intervene and at least make a hole it in. Have candled it to see if there is an internal pip but can't seem to see one. They are up to day 38. Any advice?