How much of the nutrition from things fed to chickens will get passed onto eggs?
I started feeding my chickens raw pumpkin, and apparently it has 300% Vitamin A per serving. I've been thinking about giving them more variety of foods with other health benefits.
What do you mean by '300% vit A' per serve? 300% RDI for a human?
How much nutrition goes from a chook into its egg depends on a few things.
Generally, the egg is a sort of restricted intake unit, it will be given a certain amount and no more. If the hen is especially deficient in some things, or only has enough for her own health but not enough to contribute to the egg as well, you can get things like chicks hatching with deficiency diseases or not hatching at all. If it's an unfertilized egg it will be less nutritious than it would be if the hen had a diet sufficient for both her needs and the eggs' needs.
Commercial high production layer breed hens usually have far less of every nutrient in their eggs as they have a less nutritious diet overall, just the so-called 'complete diet' (survival rations) designed to keep them basically alive and producing for a very short time, only a fraction of their potential lifespan. They are all quite malnourished almost as a rule, but their production levels depend on that, if they get everything they need they will lower production and may stop laying to moult. The diet they're kept on has been fine tuned and developed in conjunction with those breeds to specifically and deliberately keep them hungry because otherwise they don't produce as well. (That's acknowledged within the industry as being a necessity for ultra production). Economics, not the health of either the chooks or the humans who eat their eggs, is the most important bottom line there.
Home grown chooks fed extras often lay less because when kept more naturally and better fed they will slow production to levels they can sustain and manage, rather than the compelled overproduction that drives commercial hens into a prematurely aged and burned out early grave. Home grown chooks, or home kept layers who have more nutrition than the commercial 'complete feeds' added to their diet, have far greater nutrient levels in their eggs, but it still won't exceed a given level or that would play havoc with the potential embryo and resulting chick; there's some kind of physiological mechanism that regulates the levels of nutrients in their eggs.
Home grown/kept chooks will also have greater overall nutrient levels in their bodies. That's what can become harmful if for example you're overdosing on any specific mineral or vitamin etc; forcefeeding can be dangerous when they have no alternatives. In Australia you can overdose with vit A by enormous amounts, as well as some other vitamins, because the land and animals and people here are almost as a rule very deficient in that. But, before one mega-doses with anything, best to do some research on it and find out the why's and the risks and the synergy between that nutrient and others, as pretty much none of them operate or are processed in isolation, they require the interaction of other nutrients in a certain ratio to do their job properly. For anyone who wants the best health for their animals or family, study of nutrition is invaluable.
Best wishes.
