We have chickens and ducks together - 3 female Pekin ducks and 18 mixed breed chickens, including one Russian Orloff rooster over the whole group of females. We had our ducks separated from the chickens when we had more ducks. We had 12 ducks and they were turning our yard into a huge mud puddle, so we sent some to freezer camp and then moved the remaining in with our chickens. They all get along really well - now the ducks don't have constant access to a pool in their run, so that helps the mud puddle issue.