a little something here wolfponies don't eat cows (even though theirs don't talk) because they need to have milk like ponies do in equestria, but the basic urge to eat meat is there maybe due to the instinct of hunting big game like deer or the urge is controllable to wolfponies on the verge of transformation but for wolfponies who are not born as a wolfpony is a bot harder but still can control it (to some degree), or maybe both who knows.

but Thomas also has other symptoms like

urge to howl with the instinct of calling other wolves and whimpering when sad.

the other ponies can see this because they have knowledge of wolfponies somehow but Thomas's dad knows too but does not want it to be true and does not want his son to worry but one night it happened…

more to come soon