I've never used a mobile coop - I must have a very strong and secure structure; my neighbor lost his whole flock to the wolves - but if it helps, this is my arrangement:
I keep all of my birds -
chickens, ducks, and geese - in one coop with no problems. The coop is a 12x16 shed. I've divided the floor space into separate sections for the ducks and geese, and I have perches along the side walls and nest boxes in the back for the
chickens.
I rotate the flock around the pasture without any fencing by putting the waterers and pools in the preferred location. The birds will tend to congregate around that for the day and then return to the coop
yard around sunset. In my
experience, the flock generally stays within a 200-300 foot radius. The ducks are, by far, the least adventurous. They prefer to spend the day gossiping around the
water cooler. The
chickens vary, not so much by breed, but by individual. Most of them keep to the range, but there are always a few adventurers. And the geese prefer to be with me.
The upside is that between the cocks and the ganders, the flock is well protected against small predators that might otherwise snatch a hen or a duck. The downside is that the ganders can be a bit of a problem. (Yes, I have had to pull an amorous gander off a hapless drake.) Anyhow, I've never had any problems with the chickens, even with the size differences among breeds, as long as the cock to hen ratio is reasonable. Just be sure to put your meat cockerels in the freezer before they can run your layer hens ragged and you
should be just fine.
Best of luck to you! And please let us know how it goes.
- Marissa
The Flock
Chickens - Silver Wyandottes, Golden Wyandottes, Light Brahmas, Dark Brahmas, Black Giants, and Dark Cornish (but never again)
Ducks - Black Swedish, Blue Swedish, and Buff
Geese - Toulouse and Buff