If you liked Birdy, you might also like...
War Horse
The Thin Red Line
Full Metal Jacket
Platoon
Apocalypse Now
The Deer Hunter
Please add other Drama/War films to this list.
it reminded me very much of 'equus', a film about a boy obsessed with horses.
https://www.imdb.com/title/tt0075995/?ref_=fn_al_tt_1