他肚子饿了is correct compare to 他的肚子饿了。 here the 肚子饿了 is that he si in the status of hungry ， so他肚子饿了=他饿了 。 他饿了 is use widely in northern china while 他肚子饿了 use in southern china more 。 no matter 他肚子饿了 or 他饿了， there is no 的 in it 。 and you can say 他的肚子咕咕叫了/ 他肚子咕咕叫了 means 他饿了。 but i think . there is one case can usa 他的肚子饿了， that is in the stories for children or oral that talk a kid ， its childishness and lovely coz in this case the 肚子 is the subject substitute the boy itself。

use “了” in the end. 我的肚子饿了 and 我肚子饿了 basically have no difference. but since the latter one is shorter, I think people will use it more often.

They both are correct but the second one is more common. Normally we chinese say"他肚子饿".

both are right！

i teach you the best and the semplest chinese word " 饿"