It's day 29 and still no pip

[Quacks and clucks]

Hey, I set 6 call duck eggs on the 24th of march and only one of them is valid, it's now day 29 and I've heard no peeping, seen no pipping and I can't tell if it's internally pipped or not... Me being the impatient person I am candled it today making sure I didn't move it from its original position, he's still kicking and moving but I'm worried there's something wrong? Should I be worried?
Many thanks

 

[Chick-N-Fun]

Welcome to our FUNomenal Flock!
Pull up a roost & enjoy your time here!
Good luck with your hatch!

 

[DucksAreBest]

Hello, welcome to BackYard Chickens! Thank you for joining our community. Was your temperature steady throughout the incubation process?
@MGG

 

[sourland]

Welcome to BYC - good luck for a successful hatch.

 

[N F C]

I've never had ducks, but I'm sure someone over on the Ducks forum could help you out:
Ducks

Best wishes!

 

[BlueBaby]

Hello, and welcome! I hope that your little duckling hatche's!

 

[416bigbore]

Hello and welcome to BYC, You found an Awesome poultry Forum to be a part of with many great knowledgeable members who are more then willing to jump in and help you with any questions you may have.

 

[DobieLover]

Hello and welcome to BYC! Glad you joined.
Good luck with the hatch.

 

[CluckerFamily]

Welcome to BYC!!

 

[drumstick diva]

SENDING GOOD HATCHING VIBES YOUR WAY