What’s the average size of a 3-week old chick?

[Megaletta]

I’m a first time chicken owner and am a little confused as to how big my chicks should be at week 3. They ate an organic chick seed mix the first week and a half (from the breeder) and have been on the medicated crumbles since then.

I have one chick that is ill and definitely a little undersized. I’m trying to figure out if the other two are on track (they are three diff breeds so harder to compare against each other). I have a salmon faverolle, blue ameracaunna, and lavender Orpington that turned three weeks today.

Does anyone have pictures they can share of what their 3-week chicks looked like (size, feather development, comb development).

thanks!

 

[Megaletta]

Here are my Orpington and ameracaunna