I really don't know why she is so much smaller - she could be younger than you were told, could be genetics or she just is not thriving like she should -there's just really no way to know.We treated the room too we have been bringing them outside to dust bathe and get fresh air and sunshine but right now it’s raining
Millie was laying eggs a few day ago but she isn’t now
We are feeding them a flock feed that is 18% protein
I gave her a scrambled egg and she and Millie enjoyed
Also do you have any idea why she is so small
She is doing much better
All you can do is see that she is eating a balanced poultry feed at least 95% of the time.
Limit treats and make those something good for her like egg, meat or fish. I would also give her poultry vitamins once a week to give her a boost.