I just placed another order with Metzer's... an embden pair and 3 more welsh harlequins! They will be a week younger than my 10 ducklings, will I be able to put them all in the same brooder or will I have to have two brooders?
hmm, what if i did two brooders, one for the first and one for the second, and then moved a couple of the older ducklings each day into the brooder with the newbies. would that make integrating them easier?
I would try and just keep an eye out to see how they do together.
Last year I bought 2 Mallard ducklings that were male, 3 weeks later a snake got one and killed it. I went out a few days later and bought 3 lil mallard girls that were 2 days old. I put the drake in with the girls and he immediatly acted like a Mamma duck to them. I've had them all a year now and he still watches after his gals really well.
I was hatching weekly for months on end- and had to combine hatches in brooders very often. I would wait until the new babies were a few days old- eating and drinking well before combining them - but I have never had any problems with a weeks difference in age. Two or three weeks and the size difference is so great that the little ones could be easily trampled - but you should be ok to just have the one brooder.