Same breed/ age size difference???

[Vratnyjulez]

I have two black Cooper marans that I got from the same hatchery same patch date and their sizes are much different any ideas why. Their hatch date is March 29 which makes them nine weeks

 

[Lady of McCamley]

Unless she also had a bantam strain, it looks like you have a bit of "failure to thrive." Some chicks just don't grow as fast or do as well. Sometimes they catch up eventually. Other times they remain unthrifty.

Hopefully it is simply a slow grower.

LofMc