A good first attempt
I'm guessing that you didn't use an editing programme on these? and they are straight out the camera except for a resize?
Just because you can, it doesn't mean you have to post a large size. Images will degenerate, at the longer end of the zoom range, with bridge / compact camera's.
Try and avoid messy backgrounds like EEO #2, the people are a distraction as is the colourful Hydrangeas(?)
Having said that, its not easy to hide fences, particular with the larger cats, and you've done quite well, in general
There is also a lot more detail to be had from the images, I've picked on the cats as an example, as I like the big cats.
All I've done is reduced the physical sizes, tweaked the brightness, and sharpened them up a little.
And a quick go with the clone tool to remove the fence.
I hope that helps?
Thanks Cobra, they were straight out of the camera (Canon 750D with 70 - 300mm lens).
The lions (not posted) I couldn't hide the fences, so not happy with those..
I have not yet got to grips with post processing and only have DPP, although heading towards Lightroom.
Thanks for the edit, it's helpful to see how what others do to images.