Setting from pullet eggs was a technique advocated years ago as a means of creating a 'bantamised' version of many standard breeds.
It was/is a slow selective process, each generation breeding from the smallest eggs from the smallest pullets each year, rearing the progeny leanly. The term 'leanly' does not imply starvation, but lower protein levels in the growth stages, with little high protein crumble type foods when out of the brooder, at which time they are allowed free range and a grain ration daily, this grain ration usually contains oats which has less protein than other grains. This technique was also used on purebred commercial farms to prevent breeds like leghorn males blowing out in the comb, the hunger was satisfied without further growth to the comb etc.
The result however was a true 'purebred' version of the standard breed without the necessity to outcross to any other bantam breed to achieve the result.
Many of our best true to type bantam breeds were produced this way in the last 100+ yrs.
It's a breeding strategy I use in breeding my Malay bantams or improving breed type when needed.
Malay Game specialist Std & bantam. Breeding since 1968, interested in breed since 1950's