Swamp Yankee,
Here is a
link where where you can find places to catch brown bullhead in your state. Here is another
link where the state reports where they have stocked bullheads. You only need one of each sex for reproduction. If you caught 5 the probability you would have at least one of each sex is > 90%. Now until Fall is the time to catch them so they would be fit and ready to spawn next year. This would work provided there are no rules regarding transplanting fish into your private waters in your state. You could take the girls for an outing and I'd bet they will never forget the trip and stocking the pond.
Alot of farm ponds have been stocked this way. If stocked alone, based on my grandfather's pond, this might be what to expect. They will live about 6 years typically and will top out around 12". They bite anything and feed the entire water column. You can catch them under bobber easily. Kids like action and bullheads will bite. Their spines can puncture a young one's hand. Same with channel catfish. We use a debarbed (with pliers) hook which makes unhooking channels easy.
My grandfathers pond was muddy. It was built on hardpan clay and was chock full of Bullhead. Whether yours would get muddy, might depend in part on the type of soil you have and how thick the muck is on the pond bottom.
