Letting New Chickens Roam Free

I am new to chickens but have learned much from this website in the last couple months - thank you!

In my neighborhood there are 2 roosters & 1 hen (Banties) that don't seem to live anywhere in particular, they started coming around about 6 months ago. They seem to roost at night 2 houses down from us & spend their days wandering our yard & a couple other yards, & yes we fed them because it was cool to have them around & they are fun to watch & we have enjoyed them.

A couple months ago the hen layed 9 eggs in our hay, none hatched. Apparently a while back she layed more because she showed up in front with babies. Found her nest & it was under a tarp behind some panels. We caught 4 of the babies because I want to tame them & have them. My question is, once these 4 are tamed & can be handled & are old enough to roam free, will they join up with the others & leave when the others leave at night or is there a chance the others will decide to move in to the coop with the new ones or will they even get along at all? I want them to be able to be free during the day but come to their coop at night then be let back out during the day, i don't want to keep them "cooped up" all the time. The fencing around our yard is not chicken proof so the others come into the back area & they will meet up at some point. 

Thanks in advance for any help..

Thanks for the replies. The 4 chicks we took from the ones that aren't ours are my flock, they're my first chickens. The ones that aren't ours have access to the front & can get through or over our fence into the back, which is where mom laid her eggs. When these babies are old enough we will move them to a coop (watching some on ebay) in our back area, then when they are old enough to range free I'd like to let them, but want to know if they'll know to come back to their coop & not wander off with the ones that aren't ours. I've heard they won't recognize mom & that she won't recognize them. Thanks again for all the help & information available..

Thanks so much for the advice. I really appreciate it & look forward to learning much more since this is all new for me.

Two Roosters

Mom hen with three of the babies

Mom hen & rooster in flowerbed

My four new babies

Thanks for the info about them, we only knew they wereBantams because the lady across the street called them banties. I couldn't even estimate their weight, but they seem about half the size of other chickens in the area.

From what I can gather from reading the forums, I can put the babies in their coop at about 4-6 weeks old, then after a couple weeks start letting them out to free range an hour or so before sunset, gradually increasing their time out until they're out all day. Am I understanding that correctly? Thanks again for all the advice & help!