No, your toilets probably aren't bad. It doesn't sound like the problem is restricted to just one fixture, so we have to assume something that affects all of them has gone awry. Our guess is that your water supply is high in mineral content. Mineral salts have a tendency to build up at the siphon jet ports under the inside rim of your toilet. This causes a slow down in the gravity feed (the force that moves the water from the holding tank to the bowl). The restriction also slows the spin of the water in your bowl and diminishes its' flushing power.

Solution: Thoroughly clean the underside of your bowl rim to clear those port openings. And, it might be a good idea for you to run wire through the holes into the hollow portion of the rim to insure that it is free and clear. A good flush results when 1) the holding tank is full, 2) all siphon jet ports are clean and clear and 3) the toilet trap and adjacent waste lines and vents are clean and free of obstructions.