I know a guy who uses a piece of chiken brest and a night crawler but remember if they don't put any fish in the lake it won't matter what bait you use. In the spring the pay lakes will put lots of fish in there pounds to get you to come fishing and then they will stop or will put very few in there and that is how they make there money.. Make sure you know when they stock it and if you can be there when they do so you will know there is fish to be caught. Alot people don't know that most of these catfish come from the ohio river.. Just a little food for thought.
+1 on the chicken liver, I always catch cats with chicken liver. Went to a pay lake in NKY one time with the wife. Must have been 50 people set up on a lake about 1 acre in size, no one was catchng anything around us but my wife pulled in three nice cats about 3lbs a piece within an hour and a half and everyone was just kinda looking at her like "damn, what they using for bait?". But you got to understand, my wife is one lucky person. The type of person that finds 4 leaf clovers on a regular basis. Never seen nothing like it, she will be walking along and then all the sudden "oh look, a four leaf clover".
I used to pay lake alot, and might be doing some here real soon due to the big lakes being flooded out and hard to launch a boat. If i had to choose one bait that i would never leave the house with, it would be white raw shrimp. It can get pricey, but you can find it on sale and cut it in chunks. Don't need a huge piece. Keep the unused pieces frozen to stretch your bait. Numerous raw chicken flavors. Cut the chicken in bite size pieces and soak them strawberry jello mix. Chicken and anise extract is a real good one. Cut chicken and honey mustard works. A good nightime bait is cut chicken marinated with sardines in soybean oil. All you need is the oil from a 50 cent can. You can also tip all these baits with a piece of night crawler. Straight nightcrawler also seems to work when they seem to not want to bite. In the summer smaller baits like wax worm, crickets, and especially catapala worms, and doe bait, but that's a whole different topic. Like stated above, you also have to know how to fish them, or your bait won't matter. Try to stay about a foot off the bottom whatever the depth is, but they will also suspend sometimes over deeper water. Would fill my basket about everytime. I also have heard that alot of the paylake fish come from the ohio. I hope mine were farm raised as advertised when i think about the number of cats that i have eaten.