Welcome, DaffyDuck100 Mallards are much smaller than Pekins. While an all female group would probably get along - it is really up to the individual ducks - I would worry about a big Pekin male mating a little mallard female, especially if there were only two or three females. Rule of thumb is 3 to 6 females per drake (male). There are exceptions to the rules all over the place, I am sharing what I feel would be healthiest for the ducks, and cause you the least grief. If you have all girl ducks, then together with the chickens could probably work out (again, it's up to them). But it is dangerous for the chickens to be with a drake, many drakes will try to mate with the chicken and seriously injure or kill them due to mismatched equipment. Ducks need a flock. I feel it is a tremendous responsibility to only have one duck, because I would need to be with the duck 24/7 for it to be content. So I have a flock of 12 girls and one boy. Originally we had eleven runners. Two died of illness, and then we adopted buffs, so we are up to thirteen now. Four sounds like a good number. If you spend time with them and they know you are the bringer of good food, and you are gentle and friendly, I think you can have a good relationship with them. Some ducks are very friendly, some less so. In our flock, there are three or four who will let me pet them - when they feel like it .