Nightly News | June 26, 2013
>>> finally tonight, a decision that will have a huge impact on the animal world . the u.s. is the only developmeed nation to do medical invasive testing, the fda says hundreds will be able to live their days out in peace.
>> reporter: after as many as 30 years in research labs, four retired lab chimps are introduced to their new yard and see the sky without bars for the first time inheir lis. they look up, climb, look up again. amy fultz helped found the national chimpanzee refugee in indiana known as chimp haven.
>> it looks like wonder and amazement.
>> reporter: twila is a wall walker, afraid to let go of the steel and concrete she has known all her life. others go into the forest for the first time with their new group of friends. today's decision means 300 more federally owned research chimps will be retired to walk on the grass and swing on the trees.
>> it's movement for a new and compassionate era on how we oversee research on our closest relatives.
>> reporter: only 50 chimps will be available for research. this is based on further opposition to research on those so much like us. some scientists argument today's move will slow medical breakthroughs.
>> reporter: federal health ramifications likely the delay of development for certain cures.
>> reporter: those who cared for chimps in the lab say retiring them is the right thing to do.
>> because of what they've gone through and what they've given to us, and not by choice.
>> reporter: a new life in a new world, for creatures so much like us. lisa myers , nbc news, louisiana.