Interwar recipes for chicken feed

[Perris]

What I'm finding most interesting this time I looked at it, is how uneven the consumption of several of the ingredients was:
The group eating the separated ingredients ate 35 grams of salt the first two weeks, 5 g the third week, 0 in the fourth and fifth weeks, 100 g the sixth week, 110 g the seventh week, 40 in the 8th week.

this is indeed interesting. But I suspect it is more 'effect' than 'cause' with growing chicks; their appetites would have been responding to the body's self-monitoring and -regulating systems, and the organs and other bodily tissues grow at various rates, so need different things at different times. Pica in a pregnant woman is the most obvious example today.

Having the same nutrients in every bite at every meal every day as per a pellet of concentrated feed is as far from natural or normal as it is possible to imagine. Before the last 80 odd years of human manipulation of their diets, there were millions of years during which birds evolved to eat what they could find in their environment, and that was the only route to survival and reproduction. That isn't wiped out in an evolutionary microsecond.