In order to maintain their body temperatures, Chickadees must take in a large number of food calories which will be metabolized for body heat. Calder (1974) notes that Black-capped Chickadees ... must eat continuously during short daylight hours to stoke their metabolic fires.
Industrial sewing machines are the best option for sewing upholstery-grade fabrics such as vinyl and leather because these machines are designed to handle thicker fabrics. Industrial machines use heavier upholstery thread and often sturdier needles which penetrate the material cleanly.
The only machines that may have differential feed are sergers. I've never come across a sewing machine that has. You can create some of the techniques of differential feed by changing the tensions on the sewing machine and by using different feet. Ruffler or gathering foot for gathering fabric. Changing the pressure on the presser foot if a pressure dial is there( either on the side of tne machine or a silver knob on the top of the machine)