Research chimpanzees should be kept in groups of at least seven, with about 1,000 square feet
of outdoor space per chimp — roughly one-sixth
of an acre for
a group
of seven, according
to the proposal.
The space must include year-round outdoor access with a variety of natural surfaces such as grass, dirt and mulch, and enough climbing space to let all members of large troupes travel, feed and rest well above the ground, and with material to let them build new nests each day, the report said.