As others have noted in this thread the "muscle tone" of eggs is largely affected by freshness. This is something that you really begin to notice with [sous vide cooked eggs](http://www.seriouseats.com/2013/10/sous-vide-101-all-about-e...) where the distinction between the 'tight' and 'loose' whites can have dramatic effects.
*"As eggs age, both the yolk and the tight white membranes will get thinner and more fragile. At the same time, the tight white will leak moisture into the loose white, diluting the loose white further and causing it to become even runnier."
*"As eggs age, both the yolk and the tight white membranes will get thinner and more fragile. At the same time, the tight white will leak moisture into the loose white, diluting the loose white further and causing it to become even runnier."