Identifying bantam chicks

[BugsToBirds]

I'm pretty new to raising chickens and got six chicks from Tractor Supply a while ago, but two of the chicks aren't growing as fast as the others. They seem to be austrlorps, while the other four should be barred rocks and california greys, and I was wondering if they could be bantams, slow growers, or if there might even be something wrong with them. They haven't shown any sign of poor health, and they should be the same age, they're just small. Are there ways of knowing if a chicken is a bantam before they're fully grown?

 

[Folly's place]

Welcome!
Post pictures! Feed stores are notorious for mixing chicks into different bins, so anything is possible. Let's see them!
Also find out what hatchery they came from, and look at the breeds and colors that hatchery sells.
Mary

 

[BugsToBirds]

Thanks for the warm welcome! I couldn't get much information about their hatchery, but I did check back and see that I got them on August 16th, making them over a month old now! Here are a couple pictures that convey the size difference. The ones with the solid black backs are the ones that should be australorps and I was wondering if they might be bantams.

 

[tn_artist]

Thanks for the warm welcome! I couldn't get much information about their hatchery, but I did check back and see that I got them on August 16th, making them over a month old now! Here are a couple pictures that convey the size difference. The ones with the solid black backs are the ones that should be australorps and I was wondering if they might be bantams.

View attachment 1910877 View attachment 1910878

I'm having the same issue, but it's two Wyandottes. I posted it on the raising chicks section if you want to take a look.

 

[BugsToBirds]

Could it be because they're not the same sex? The ones I'm wondering about should be females, but the of the two straight run chicks I got one immediately fluffed up and the other is growing feathers at the same rate as all the pullets, and I just suspected I got one of each sex.