Making this post for future reference
Horse Hair direction charts
People have been asking for the source. Sorry for not adding it earlier
"An Atlas of Animal Anatomy for Artists (Dover Anatomy for Artists)" - W. Ellenberger (Author), H. BAUM (Author), H. DITTRICH (Author), LEWIS S. BROWN (Editor)
This book is the BEST. Go and buy it if you’re even remotely serious about animal art - it has loads of species, from horses and deer to cats, cows and monkeys.