@G-Sage, @Predatoxic: I have to disagree. I think a lot of them are useable as livestock (it depends on the definition of "livestock"). Let me make some example here ...
#11 and deer farming
#11 reminds me of a "mayerstic" deer. Of cause this is not a pig but there are people how have "deer farms" for commercial use. If you can farm deers why not the elegant thing with the huge antler on the head.
classic livestock #1, #3, #5, #8 and #10
#1 #3 #8 and #10 reminds me of classic buffalo or cow alike livestock creatures while #5 looks like a huge bird not capable of flying (turkey maybe).
what remains #2, #4, #6, #7 and #9
This are the ones remaining. TBH i really don't like #2 because its to skinny for a livestock creature but that's only my personal opinion. The remaining 4 creature types are unique and special and i could imagine to see these on farms (not human farms, but farms). Especially #7 reminds me on guinea-pigs which are normal "livestock" creatures in south-america(Extra Link) while they are only "pets" in europe. It's really depending on the definition and your origin what is livestock for you and what's not and therefore i would accept them all.
@claudiotolomei for me your creatures are plausible and mostly natural inspired. I could imagine to see them ingame and build a farm with them. good work as always.