Mixed hatching eggs... ducks and chickens

[UrbanFarmerGreg]

I have had a silkie hen sitting on 4 duck eggs for about 5 days now and was wondering about putting some silkie eggs under her too... just wondering if this is ok to do or is it not a good idea. I have read duck eggs incubate in about 28 days and only about 21 for chickens so just wondering if its a good idea and when should the silkie eggs go under her?

 

[CayleeMarie03]

If you were to do this put the chicken eggs under when the duck eggs have been under the hen for 6-7 days.