12 at a time should be ok. how many is too many to start with depends on you and the time you have to dedicate to the chicks. My first batch of chicks I got 25 of them and of the ones that are left they run away from me any time I am near, I cannot pick them up if something is wrong, I have to wait until nighttime and it's a strong factor in my culling them this spring. My 3 new EEs, I bought from a local woman (I had 4, one was taken by a stray cat) and from day one I was able to hold them all and hand feed them all and just build a better relationship and as a result they follow me everywhere, I can let them out to free range (the others would just run away), they readily accept treats from me and don't fight my holding them. I only plan on raising poultry 10-12 at a time in the future (with the exception of meat chickens).
Raising chicks isn't difficult. keep their bedding clean and their food and water clean. Have poly-vi-sol and basic medical supplies on hand (and keep them separate from your own). My kit contains gauze, vet wrap, neosporin, mercuroclear, Vaseline, condoms (yes, more lube the better), KY Jelly, saline spray, Preparation H, scissors, baking soda, q-tips, honey, Popsicle sticks, syringes and latex gloves.
You also have to have the constitution to help them die if that is what needs to be done.
On that happy note, good luck!
