What is the chance of my broody hen accepting about a week old chicks as her own chick?

[Luckybaby]

I bought 2 less than a week old chicks from the pet store about 2 days ago, and I tried to put them inside the cage of another broody hen, during afternoon hours. The broody hen have about 15-18 day old chicks on that time, and surprisingly, she accepted them as her own chick. However, between 1am to 2 am, when one of the new chick under her, went out to eat and drink, she started pecking it. After that, I took out both of them to put them in a brooder. I have another broody hen, who is incubating eggs that may hatch at least 2 days from now. Do you think the broody hen will accept those chicks who will be more than a week old by that time, if I sneak it under her, when the chicks are hatching during the night?

 

[Nature Gurl]

I don't personally think that would work. There would be such a difference in the chicks compared to the new hatch. Also chicks have the mother imprinted in them within a very short time after hatching so my greater concern would be whether or not the chicks would accept the hen as their mother. Seems risky but maybe someone else has had good luck doing that.

 

[CindaLouWho]

Seems like too large of an age gap, but I suppose it's worth a shot.
My hen hatched one egg, so I purchased a second chick from the feed store. The only ones they had that were similar size were a bantam breed. The hen accepted it as her own immediately; though it is at least 3 days older than her own hatched chick; she cares for it as if it is her own.

 

[Luckybaby]

I tried to sneak both of them last night. Few minutes after she saw them and after I turned on the light, she started pecking them, so I took them out and put them back to the brooder. Did I do something wrong, or she just know which is her chicks and she is unwilling to adopt other chicks? I turned on the lights about 20 minutes after I put them in, since she started pecking them even if her cage is mostly dark. There was a little bit of street light shining through her cage when I sneak them in and when she pecks them.

 

[CindaLouWho]

She's seeing them as a threat to her babies. Best to raise them yourself if she won't accept them.