shrink wrapped indicates low humidity during incubation or hatch. If the eggs were piped then hatch incubation was very low.
people tend to spit out a number for humidity but that really doesn't work as there to many factors to consider. Around 40% during incubation will give you a starting point that you can adjust at day 9-10 when you candle them and see the size of the air pocket. Depending on the humidity In the room and a load of other things like the incubator design don't be scared to increase the humidity above what people recommend if the air pocket is to large.
Ive read about people running low 20's to people running 50 plus based on the air pocket (80% of all humidity sensors can be a little off the other 20% are just way the hell off)
What everyone agrees on ........ well nearly everyone is that during lockdown the humidity needs to be high. Suggested is 70% plus I see that as a minimum but like I said it depends on a lot of things. Generally if you see condensation on the glass/plastic its to high unless you live in a cold area then even that may be ok.
most people drown there chicks during hatch due to very high humidity during incubation so don't go nuts and go super high on the humidity to start.