For the most bang for your buck, do these: 1) get a breed that likes to brood. My lovely Banty Welsummer hen wanted to hatch eggs even before she had a mate. (OMW, the nasty things she called us when we "stole" her eggs! Damn humans, can't trust 'em at all ...) 2) Get your girl(s) a mate. I recommend the same breed, unless you plan to make hybrids on purpose. We got 2 boy Welsummer Bantams and she chose the nicer one. The other left home, after his advances were spurned. 3) Let Nature take her course, while you assist as needed.
Our biggest challenge was to locate where our crazy bird hid her eggs. We moved her, and all 10 eggs, one night after dark to a lockable cage to keep them all safe from predators (we've had trouble with rats, owls, snakes, opossums, & raccoons). Every morning, we opened her door so she could spend 15 minutes eating & drinking before she returned to sitting duty; every evening we locked it again. Three weeks later, 9 baby chicks were born over a 48 hr period. Whoda thunk...9 outta 10 hatched! Ok. (The next time, we only let her have 2, and only 1 hatched.) Her flock-mate, a giant gray mixed-breed hen, took pity on poor Goldie and started helping with the baby duties, especially snuggling them to keep warm and finding bugs to eat. All nine babies mixed in with the other adults: no drama, fighting, bloodshed, etc. Daddy would chase them if the strayed too far from either "mom", and give them a little peck to make them return. He acted like a gentle herd dog, keeping those 9 hatchlings near their moms for safety. One tiny one was attacked by our Ancona flock after getting into their cage, and unable to get out in time.
But the rest grew up healthy & gorgeous, and the boys learned how to court the hens properly from their dad. Every time I try to introduce babies into an existing flock, it doesn't go well. This is why we have the Ancona's separate. Everyday, we let the Easter Egger hens out of their pen for several hours, and they mingle with the Welsummers, who have the run of the yard in the daytime. Goldie makes sure sure everyone stays a respectful distance from her kids while they are young. When they are about 3 months old, she stops the mothering and returns to mating with Mollie and laying eggs. I noticed the babies make a "peeping" sound when they are young, and as soon as the sound changes and they begin to sound like real chickens, mom cuts them off. She doesn't find bugs for them, doesn't let them eat 1st, & doesn't run interference if they are approached by another flock-mate. This one hen could conceivably hatch about 25 chicks a year, over 3 hatchings. Plus her daughters could begin to lay viable eggs at 5 or 6 months of age. If you let them all hatch, you will be knee deep in chicken in a year.
I guess it depends on your goals. We were very tired of separate housing for each group of hens (with separate food & water dishes to be filled & cleaned, hay to be laid then mulched, etc) , and wanted friendlier relations on out Urban Farmstead. We sure got that with our lovely mixed flock, thanks to our broody hen, Goldie.
