Thanks to PeepsCA, I learned quite a bit about my little keets that I've had in a mixed brooder... Right now, I'm feeding a fermented starter feed - fermentation increases the amount of available protein. In addition, I add kefir and meal worms. It's probably more protein than my chicks need; but, it's not quite as much as the keets would generally get. I'd say (I'm guesstimating) that I'm running roughly 25-26% protein. It could be more; but, I'd only be guessing.
There are 4 week old keets, 2 week old chicks, and five day old keets in the brooder together. PeepsCA, don't pass out...remember, I've a decent sized brooder. Plenty of temperature variation if they need to move around. **grins**
It's a 3:1:1:.5 ratio that I use on my feed for them. Three parts fermented starter feed (a mash that is 20% protein dry - increases to about 23% when fermented). One part dry feed (so that I can put it on that lid and not have it pour out everywhere). One part kefir and half part meal worms. There's been no cannibalism attempted and the bigger ones actually play care takers to the smaller ones, so I'm guessing the protein ratios are working out ok.
That's 20 chicks and 10 keets in a 10'x2.5' brooder, if you were wondering