HollowOfWisps
Previously AstroDuck
I have had over 40 orpingtons and from my experience they feather/grow slower than other breeds. With heritage breeds usually the larger they are expected to get the slower they grow.You can’t compare feathering and growth rates between different breeds. Even then within the same breed you can have different blood lines that will affect growth rates. An Orpington chick with older English bloodlines will grow more slowly compared to one with more modern Orpington bloodlines.