I have had a trio of jumbo pekins in the same pen as my trio of chickens at night for about 2 years now. All 6 of them are ages 4-2, no babies, and during the day, 7 am - just before sunset they are all out to grazy, play in pond, eat bugs whatever. I've NEVER had any problems, even feeding, ducks would eat out of a dog bowl, chickens eat their scratch. I pen up my goats ( separate pen ), change water, whatever so I watch them every night eating. Their pen is 10'x20', the chicken coop is 3 feet off the ground and chicken sleeping space, ducks have a spot on the ground, similar housing design, just another house. I can post pic if needed.
This morning I went out to let everyone out and one of my female ducks ( 2 yr old ), was dead, my male was standing guard over the remaining female. I don't understand what would cause the change, is it even safe to let everyone roam during the day? I'm building a new pen today, my ducks and chickens will not spend another night together. I'm just dumbfounded, and this was so blindsided hurts my heart for that poor girl, want to understand why, so I can prevent something so needlessly again.
Oh I should say, hubby works nights so someone is always home to keep and eye on all the animals, during the day grazing time, fenced in acre for fowl :-)