I put special attention into splitting birds up this year for breeding.  Our big breeding pen contains 4 pairs of mallards, 3 pair of redheads, a trio of pintails, 12 pairs of wooducks, 2 pair of mandarin, a pair of cans, a trio of shovelers, and a trio of lesser scaup, plus a few single birds.  We just added on to this pen last year twice and we are now adding another portion with about a 20 foot long, 4 foot deep pool.  So i make sure they have plenty of space in there, they have 3 other big pools throughout the pen.  I made sure our black ducks were separated this year, as I learned they were half the reason I lost parent hatched wooducks because they kill any other ducklings besides their own.  I am keeping my Anconas away from the exotics.  I completely agree with what you said about people on this forum who tell people false information.  I am a member of gbwf and it is a great site for learning about birds from reliable sources.  My dad has been raising birds for 30+ years and has taught me all about it but we still learn more everyday.