There is this movie that involves a group of adult forest animals that have to leave their home because humans have poisoned their land. On their journey they have to overcome trials such as; a farmer and his gun, and a busy highway road. Some of the animals die because they cannot overcome their instincts. I have looked for this movie for so long!!

The Animals of Farthing Wood (1993–95 TV series)
IMDb synopsis;
The series is about a gathering of animals who must immigrate towards a paradise called White Deer Park while making new friends and avoiding dangerous obstacles along the way. The second season continues with The animals facing a rivalry of Blue Foxes to stay in the park while fighting winter and losing family members. The final season indicated a battle against a bullying bunch of rats who want the park for themselves after the great White Stag has died. The park needs not only a new leader but also a miracle to fight against the rats to the end.

The Animals of Farthing Wood (TV Series 1993 (http://www.imdb.com/title/tt0286336/)