[Prod]

Forgive what might be a daft question, but if you don't ask you don't learn!!   I have 2 pairs of Call Ducks that are laying and a friend has offered to incubate the eggs for me as he has never hatched ducks before & has taken a shine to mine.  At the same time I have asked him to hatch a couple of my chickens eggs. I have a Welsummer cockerel  and various chickens.  It would be interesting to see what we get however (for example from a Cream Legbar or Marans)  I am right in thinking I would not be wise to introduce any of the chicks/ducklings back into my flock as they will be related???

[joyfull]

being related is not the problem - the problem comes with the hatching of further eggs. You should never hatch eggs from a brother and sister (dad to daughter and grand daughter is fine).
As they wont be introduced with a broody hen then you would be best waiting until they are of a similar size to your other birds.

[ANHBUC]

Is he hoping to put all the eggs (ducks/hens) in the incubator at the same time?  I think they will need different conditions (heat/humidity/times) to hatch.   

[Prod]

So If I understand this  when (if)  they hatch it would be ok for my existing cockerel to mate with any females???   I wouldn't be keeping any cockerels that hatch so I don't think the brother/sister will apply.  He has more than one incubator  so should be ok otherwise I will leave hatching the chickens for now. Thanks for replies

[joyfull]

yes just so long as he isn't their brother then mating will be fine.

[Prod]

Ok  I have to ask, why father/daughter  but not brother/sister   

[joyfull]

because brother and sisters genes will be too close however the daughters genes will only 50% the same as her fathers  .