If you're using the Dumor 20% Starter/Grower from Tractor Supply, it should work just as well as "All Flock."
I found the nutrition facts on the website:
https://www.tractorsupply.com/tsc/p...ick-strarter-grower-20-feed-50-lb-3006317-306
It's got 20% protein, 3% fat, 6% fiber, 1-1.5% calcium
That's pretty close to what
@U_Stormcrow recommended:
The only difference is that the Dumor starter is a little high in fiber (6% rather than 3.5%).
But the fiber content of Nutrena All Flock is also 6%
https://www.tractorsupply.com/tsc/product/nutrena-naturewise-all-flock-pellet-40-lb-bag
While Purina's Flock Raiser has 5% fiber
https://www.purinamills.com/chicken-feed/products/detail/purina-flock-raiser-crumbles
So I would say your current Starter/Grower is fine to use as an "All Flock" feed if you want to.