my hen went missing for 2 months i eventually found her in a ditch about 3 feilds away sitting on 2 rotten eggs she was very skinny but i fattened her up again and last year she hatched one chick but the chick died unfortuanity it jumped into a bucket of water

i have a silkie with 2 chicks that are allmost 9 weeks old when should i put them with the flock they are currently with there mother in a seperate chicken coop
allso i have 4 chicks that i hatched in an incubator when should i add them to the flock aswell just wondering.