Local, family-owned businesses might be more likely to guarantee pullets as opposed to the chain stores like Tractor Supply.
Any reason you want six-day-old chicks specifically?
@GirlsHuntToo has a good idea…
Chicken Scratch Poultry is good, they have chicks and started pullets (day-old chicks and eight-week-old chicks). They’re in McLeansboro, Illinois.
You can’t order a six-day-old chick through the mail.
Here’s the link in case you’re interested: https://chickenscratchpoultry.com/