What does " behind–the-scenes animal feeds" mean? ‘We’re going to go do some behind–the-scenes animal feeds at the zoo,’ she said.?

it means that they are going to be feeding the zoo animals, with the instruction and supervision of the keepers, in an area where the public does not normally enter such as the back area of the enclosures where the animals usually go in for the night or if they don't want to be around the crowds of people, or at a time where the public cannot normally be at the zoo, such as at night or very early in the morning.

Behind the scenes anywhere means something that the majority do not get to see. Behind the scenes at a zoo relates to areas of the zoo to which the public are not given access. This can include, but is not limited to, areas where animals sleep, give birth, receive veterinary care, and may include areas where animals are fed out of sight of the public. I might hazard a guess you are going on a "keeper-for-the-day" experience and will be granted (supervised) access to areas the public do not get to see.

behind the scenes means things that are done but people are not shown it. not public, in this case. animal feeds means the feeding of the animals. So, you are going to a zoo, and you will be let in to watch the feeding of animals that is not usually shown to the public.