Are there any differences (nuances or usage) when using prefix 子, 小 or 仔 for denoting young animals?
- Kitten: 子猫 vs 小猫 vs 仔猫
- Puppy: 子犬 vs 小犬 vs 仔犬
- Pony: 子馬 vs 小馬 vs 仔馬
- Calf: 子牛 vs 小牛 vs 仔牛
- Lamb: 子羊 vs 小羊 vs 仔羊
- Piglet: 子豚 vs 小豚 vs 仔豚
The OP's comment just now is on the right track:
小猫 certainly could be just a small cat.
I think for the anthropomorphism case those characters would need to be switched. =p
Google hits [Japanese pages only]:
子 means child. 仔 means an animal child, but does not seem to be used much regularly except for mentioning a child of a horse. 小 means small, which often means child but not necessarily.