Quote: I was thinking just this yesterday. need to know the hatch date of each bird or group of birds. Boggles the mind.
As for growth rate, it can be a matter of progress like any other trait. And time of year hatched according to some on the heritage thread. Some discussion that birds hatched later in the year do not grow the same rate as those hatched earlier in the year. Not sure why. Generally know the progression of a particular line and select from there.
Call bird-- you are referring to breese specificall y right??
Personally I think it has a lot to do one how the chicks are reared not the time of year - That's just what I think.
I was not discussing bresse in weight if that's what you are asking? This could be applied to any breed. You would just adjust target weights for the different age groups.