Chickens stand in their cages at a farm near Stuart, Iowa, in 2009. This week, bird flu hit a large poultry facility in Iowa. It's not clear how the virus is evading the industry's biosecurity efforts. Charlie Neibergall/AP hide caption

itoggle caption Charlie Neibergall/AP

Star enjoys a moment in the sun at the Chimp Haven sanctuary in Keithville, La. Brandon Wade/AP Images for The Humane Society of the United States and Chimp Haven hide caption

itoggle caption Brandon Wade/AP Images for The Humane Society of the United States and Chimp Haven

Near the Danish city of Ikast, some 1,500 spectators gathered on April 19 to celebrate what has become something of a national holiday at organic dairy farms around Denmark. Courtesy of Organic Denmark hide caption

itoggle caption Courtesy of Organic Denmark

Maya, shown with her newborn, Kip, had to use her wits to rise above her lowly station in the social hierarchy of her group of macaque monkeys. Jeff Wilson/Disney hide caption

itoggle caption Jeff Wilson/Disney

Mother and infant Bouvier's red colobus monkeys in a first-ever photograph of the primate taken in the Democratic Republic of Congo. The species was thought to have gone extinct in the 1970s. Lieven Devreese and Gaël Elie Gnondo Gobolo/Ntokou-Pikounda National Park, DRC hide caption

itoggle caption Lieven Devreese and Gaël Elie Gnondo Gobolo/Ntokou-Pikounda National Park, DRC

The mountain lion known as P-22 is seen in a photo from November after recovering from mange. He has been living in Griffith Park since at least February 2012. Courtesy of the National Park Service hide caption

itoggle caption Courtesy of the National Park Service

In Gaza, all hermaphroditic goats will go to heaven. On Sunday, authorities ordered the slaughter of this animal — which had male sex organs and udders — lest people mistakenly believe that its milk had special powers. And if another hermaphrodite goat turns up, it too will face the knife. Emily Harris/NPR hide caption

itoggle caption Emily Harris/NPR

An undated file photo provided by the Wisconsin Department of Natural Resources of a northern long-eared bat. A fungal disease has devastated the species, now listed as threatened. AP hide caption

itoggle caption AP