Great work on the mammals, they're all quite clean and readable. Not sure about the height of the cavy and pig heads, they normally hold them pretty low. Sheep could be fluffier maybe, if you're going for the iconic "cloud" sheep, although a mouflon would be a cool choice. I mentioned before, but I think the color contrast on the elephant is too strong.
While your mammals have characterful and accurate faces, I'm not sure you've quite achieved the same mastery over the birds. It took me a while to figure out what the guinea hen was (It is that, right? My first guess was one of them little geese) although I understand their flecked look is very difficult to make this small, but even if you're just dithering, black and white are a better choice I reckon.
But the peacock looks like a blue swan carrying a green clam. Maybe try it with the tail down? Otherwise you'll have to shrink it a lot to make the tail fit in the sprite area. With the tail down, it could be smaller if it's early in the season. If you do do it like this, you should be aware that the "tail" part of the feathers actually starts up on the back, which is where the most brilliant green is. And the wings are like a black and white that maybe just works out to greyish. But also be aware: There isn't a linear nature to the green bits of the tail, only the white bits. And the eyes are black and white and need to pop more, even if you can't fit as many as a very impressive display would have. As for the beak, #505050 is definitely wrong, though I'm not sure I have a better one within your palette.
Anyway, this is a lot of talk for somebody not doing any work, so here's a quick edit of your sprite to show a more realistic coloring and posture:
I'm not super happy with how striped the wings look on the male, or the tail, and the female especially looks overly goosey (I think itīs the head shape(EDIT: Changed a few pixels to address this)) but you get the idea; it's a step in the right direction anyway.
All those colors are taken from the creatures in that compilation there by the way, except the darkest blue on the male's belly since there wasn't an adequately dark example.