Threonine levels are likely higher in your fresh pullet eggs - which helps with membrane formation. They are also fresher, the amino acids haven't begun to degrade as badly.
Yes.
Egg yolks are high fat. Plastic is chemically almost identical to a fat. Ergo, egg yolks stick to plastic REALLY well. Its part of why your tupperware doesn't feel clean, even after the dishwasher on hot/hot after you have stored fatty foods in it.
To a lesser extent, egg yolks are...