Well, my Muscovies never did pip. I watched them after internal pip for 2 days, candled and saw good activity in most misted and left them another day. Yesterday still nothing, and I worried a couple were no longer moving, so went ahead and put 2 mm pips in the ones with internal pips, left the 3 without sign of internal pipping. Tonight (day 4 from first internal pipping) I opened the ones I noted to previously look like they died and without internal pips, opened and found 2 dead with internal pips, 2 dead and vessels looking dark. Also opened the one egg that looked like it quit just before lockdown, case confirmed. That left me with 5 eggs. Candling tonight showed good movement in 2, 2 without internal pips obvious, but movement noted yesterday, and one without movement but a beak visible. Worried that my babies were all dying in the egg, I figured I had to at least try with these ones or at least see what stage they were at. The two with internal pips I widened the holes, vessels look like they are beginning to receed, made enough of a hole that I can monitor them, misted the membranes and put them back. The two without pips I opened the air cells, found nice moist membranes, good vessels, but no palpable or visible beaks, just a leg and shoulder. Both had the head down in the small end, but were still alive. I gently worked through the membrane between vessels until I could insert a blunt probe under the neck and draw the head up and through the membrane for both. They are now resting with heads out but the otherwise still within the egg. Looks like they have a little yolk left to absorb. The one without movement but beak visible had mildly tacky membranes. Didn't see much movement, but did get one little movement when I poked at it. Moistened the membranes, minimal vessels could be seen, seemed mature, freed the membrane around the head and broke out the shell along the margin of the air sac and put him back. Misted the box and got the temps back up to 98. Over the next hour this last one began peeping, moving, and kicked himself free, no yolk, stool noted in shell, looks pretty normal. Hopefully he makes it. The other 4 are beginning to peep (for the first time), are making little duck motions with their bills and looking more normal. I think the O2 agrees with them. The two head down ones are breathing and resting with their heads out, now.
Well, anyway, that's my experience with them so far. I tried really hard not to intervene and I know they take time, but they looked like they were fading away on me. I think I made the right choice. Time will tell, I guess. I have no doubt that at least 3 of these 5 would never have survived, and suspect they all would have perished. Wish I knew why they did so well right up until that time, then just didn't pip.
Sorry for the rambling, just hoping some of them make it. I'm hopeful for these last 5.