We are developing feedhorn-coupled TES polarimeters to measure the polarization anisotropies of the cosmic microwave background (CMB) radiation. These devices will be deployed in arrays of hundreds to thousands and will be measured using multiplexed SQUID readout electronics. Since multiplexed devices share common circuitry, a high degree of uniformity is required in the electrothermal properties of the TES bolometers and readout circuits in order to operate all channels simultaneously with high sensitivity. Our cryogenic test bed can probe dozens of devices simultaneously, thus providing useful detector statistics on relatively short time scales. We describe the TES bolometer design and present dark (no optical loading) measurements of the electrical and thermal properties and uniformity of prototype bolometers across two 3-inch diameter production wafers, including (standard deviation in parenthesis): TES transition temperature (∼ 1%), normal resistance (∼ 10%), thermal conductance (≲ 10%), time constant (∼ 20%), shunt resistance (≲; 5%), and noise properties.