They should be fine together... just make sure they all have enough space and watch that than none of the littlest ones get picked on or trampled. I'd be also sure to provide 2 or even 3 feeders and waterers for that many babies so nobody gets crowded out and goes hungry or thirsty. And you may need 2 different heat lamps so everybody can get to the warmth if they need it.
Keep in mind that the keets require a higher protein starter food than chick starter, so try to find a Turkey, Pheasant or Game Bird starter feed containing between 25%-30% protein and make sure it is medicated with Amprolium to prevent Coccidiosis. The chicks will just pass the extra protein, but the keets need it to grow and develop at the proper rate.
Good luck with them, post pics if you can!