
someone has to nitpick.. my brother is the bio-major in my family. I just keep the critters.
Now i want a patterned belly just to see if I can prove 28" isn't the full potential size 
.. And I agree completely the science backs up all of the info. But there isn't extensive research on spiney eels out there. I always try and er on the side of caution. Very few of these species have been kept in captivity for extensive lengths of time outside Public Aquariums. Very little is actually known of these fish in the General Hobby.
OP: unpatterned belly is indeed the larger species. 24" -40" have been recorded in captivity for max sizes ( males are belived to be the smaller specimines, and a few large eels have been confirmed females.) I would be very surprized if any spiney took chicken. invertibrates, and fish are readily accepted foods. You should expect your tire track to hit 12" his first year.