I would immediately change your feeding schedule. Feed in separate rooms through whelping and until the litter has been sold. GSDs are known for moderate same sex aggression…throwing pregnancy into that mix increases that instinct.
Your breed mentor should have told you this.
We would take our childhood parakeets to the Vet to have their nails trimmed. You may be able to find a veterinarian near you who will trim parakeet nails. They are so skilled they are usually able to do it quickly causing little stress. Good luck!
As this is your first time, I’d let the vet do it first and show you how he/she does it, so that you could do it at home next time. Good luck 🙂