Hi
If you go for chicks only then you will need to separate the layers from the ones for food. They need different feeding and I think you will need different breeds. You would not get any meat of a normal grower/layer. The diary from this website shows an update for March with the chicks bought for meat, if i recall they will be culled at 10 wks give or take. A hen does not usually start laying till 20 wks.
I live in a housing scheme and my 5 chooks still make some noise especially between 8-9 in the moring, they are usually ready for coming out at first light. They also chook away after laying. They are not totally quiet.
If you have them on grass be prepared for all greenery to be eaten, mine are now on dirt and are happy scrapping away and i give them greens too supplement their diet. The garden does look like no mans land in their area but I dont mind, i change the top layer dirt regualry with the free council compost so the soil does not become too rotten, otherwise it smells.
From the 5 layers i get 4 eggs each day, i have to give them away...I find they dont like everygreens and conifers everything else is food.
Good luck