I would wait a couple of days and let the babies rest up and get their land legs under em. Then I would introduce them. The last adoption I did was over a period of days...waiting for the babies to be less dependent on heat because they were a little older. It went just fine. It has been a weird year as far as weather goes. I kept the babies in my garage under a heat lamp until they were about 12 days old. Then they moved to the barn with the rest of the flock and their adoptive trio, two geese and a gander. The babies that I earlier adopted into the flock were 5 Roman's and 3 Sebbies. They were initially adopted by three single ganders. There is another trio, (2 geese and one gander) that belong to that group. But, when the first group of babies were ready to be "out and about" the trio was busy setting on their own nests with the gander standing guard - they took over the babysitting and parenting, only after they realized their eggs were not going to hatch - now it's just one happy group of 14. The second group is the adult trio and 4 goslings. The two groups interact during the day but at night each group likes to be in its own box stall in the barn.