I started out only using the Dumor 24, and only tried the Purina 30 because I was trading chicks for feed at a store that only sold 30, 20 and 16. I was curious if the chicks would like it (I wasn't going to trade for any more bags if they didn't like it). I run 2 brooders at a time (2 incubators, 1 hatcher, 2 brooders), so I used the 30 in one of the brooders with the same hatch - and the 30 chicks looked more robust and active. I have friends that raise their quail with their chickens, on 20% chicken feed - and their birds and eggs are much smaller than ours. We've traded eggs - and their eggs grow into birds as large as ours if we feed them the same. Whether it's the extra protein or just that they eat more when it is what they prefer I don't know. I grind the feed for the chicks in the brooders, but not once they go outside. What I haven't checked is whether the older birds only prefer the 24% when they aren't ground (my daughter likes to do comparisons like this for science projects).