Help with humidity in my bator

[Squishypuff]

I've got an LG still air (I know, they're junk, but they are in my budget so...) and have run around 5 sets of eggs. First set, no eggs hatched. Shrink wrapped. Second, 5 hatched and lived. Third, shrinkwrapped. Fourth... same... Fifth...same...

I can keep the temp stable no problem and the chicks are all developing right up till the end, but I cannot keep the humidity in it. It won't go over 45% and that is with a huge shallow pan of water, wet paper towels, and sponges in it. I'm so frustrated. I have another batch of eggs (they're free, so why not try, right?) in there and need some ideas for making this hatch successful. I thought about putting the whole bator into a trash bag with just the two little top holes on the top of the bator open for air flow... Good idea, or idiotic? I'm desperate! And no, I don't have the option of buying a better bator right now, so any help with modifying this one would be much appreciated!

 

[Christie Rhae]

Do you have all the plugs in and not opening incubator at all? I could not get humidity up until I placed a jar of water with a sponge half in. If even that does not get humidity up... make sure your humidity gauge is working... I keep two in the incubator.
So what does shrink wrapped mean to you? Describe it. Only reason I ask is I thought I knew what shrink wrapped was until I really had one... dang that chick was STUCK in the membrane...I mean glued. I hatched a batch of chicks, thought all the eggs that were gonna hatch were done... I just left the incubator on....cuz I dunno. I hadn't added any water and two days later I checked and there was a chick that had pipped and zipped and was totally glued into that shell. I had to perform emergency chick-endectomy! lol Lots of warm paper towels and Qtips got that little bugger out.

 

[Squishypuff]

No, I was told not to leave the plugs in during hatching because the chicks needed the oxygen flow coming in. So they've been open for all the hatches.

Shrink wrapped to me- chicks that were so tightly wrapped in membrane that most of the egg was empty and it was nearly impossible to pry off the membrane for an "eggtopsy." A few were still alive, and I tried spraying a mist of water to help them but they all died.

I don't open the bator during lockdown except once i think everything has hatched that is going to hatch. Hard to keep hands off though!

 

[Christie Rhae]

Hmmm... well the egg does need to look to be about 1/3 empty when they hatch because they need to be able to turn and zip out. The eggs are supposed to lose weight during incubation. I have had chicks die in the shell without internally pipping through that membrane. But when I touch the membrane it is not dry and hard. So I didn't consider that shrink wrapped.
I understood that shrink-wrapping happened after the chick pipped and moisture escapes through the pipped hole or zipped shell. At that time it is so important that there is enough moisture in the air so that the inside of the egg does not dry out too much. Before the egg has a hole in it, it does not usually lose too much moisture through the shell.
I keep the humidity very low during incubation (20%) and then put in all the plugs and fill up the water channels and add a jar of water with a sponge to get humidity up over 60%. This seems to work well for me.
The styrofoam incubators have holes in the bottom and small holes in other places for airflow.
Not sure what else could be the problem.