I've worked in upstate NY, between Syracuse and Rochester. There were lakes of varying sizes on that private preserve. In the smaller ponds, their bluegills didn't spawn until early June, and in the bigger, deeper lakes, it could be as late as July. They spawned once per year and grew fast. When we started a limited supplemental feeding program in the second year, (with a high protein feed), we saw fish in better condition and two spawns in small ponds. In the water with heavy spring vegetation that invaded the best spawning areas, spawning was reduced...the bluegills couldn't efficiently get to their beds. Just for giggles, we raked some plants (curly-leafed pondweed) off from known spawning beds and the bluegills came right in and did their business in two feet of water. I believe timing was important for that. If we'd waited another week or two, odds are the fish wouldn't have spawned.
Here's my parting shot from lots of years messing with fish...just because you can't see them doesn't mean they aren't there. If the neighbor's bluegills have spawned, yours probably have as well. It could be that you have much better escape cover and habitat with good food that your fish don't have to come to the edge seeking protection and a cafeteria.
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