Which chick is older?

[OFWGKTA]

i hatched these two chicks who look exactly alike, either from my silkie hen, chip, or my silkie rooster, pringle, ive always deemed the bigger one to be older, and i still personally belive that the big baby is older, but the tail growth is just throwing me off, ive seen signs that the smaller one is developing faster, big baby is tall, is growing more feathers, but little baby is getting a really long tail feather, and is starting to develop feathers too. Help? (BIG BABY PICTURES ON TOP, LITTLE BABY ON BOTTOM)
big baby--->

little baby --->

 

[nuthatched]

You don't know when they hatched?
The bottom one looks to be a week younger

 

[OFWGKTA]

You don't know when they hatched?
The bottom one looks to be a week younger

I know one hatched about 3 weeks ago. I had them checked up in my notes app but then i forgot after the third baby hatched