So in a few weeks I'll be getting my first chicks. along with my layers I wanted to try raising a few meat chickens too. I've been reading that meat chickens and egg chickens need different types of starter feed, I was wondering how vital this is, I don't really have the space to keep them separated, can I make a 50/50 mix of both feeds or is there one feed I can use for both types of chicks?
The issue with co-housing is about more than just the type of feed. What kind of meat chicks are you getting - there will be a difference in how significant the issues might be if you are getting Cornish Cross vs. the slower growing ranger type. Are you planning to pasture the flock before processing the meaties?
Cornish Cross will outpace the growth of your laying chicks by the end of the first week. By the end of the second week they will look like giants among the other chicks - and this will continue, with an ever growing disparity in the size of the two types of birds. This presents the issues of bullying and overcrowding. Further, it is the nature of the Cornish Cross to plant themselves at the feed station and not move - often laying next to the feeder all day (this is in part due to the progressive mobility issues they experience with the rapid growth) - as you can imagine, this makes it difficult for any other birds, particularly smaller, less aggressive chicks such as your layers, to reach the feed.
Then there is the issue of housekeeping - due to the nature of the Cornish Cross, the volume of waste expelled by that half of your flock is going to be overwhelming. Part of keeping a healthy flock, especially for the birds that will be intended for long-term use in the laying flock, is keeping a clean, healthy environment as they are developing.
More than the starter issue, the potential issue would be the finishing process - and this will depend on your planned feed program as you grow them out from hatchling to processed birds. Are you going to follow the traditional/standard feed plan for them?
Ultimately, the feed issue would be the last thing on my list of concerns and the last reason I would consider for not co-habbing the two groups.