I'll let you know my thoughts about animal related jobs. A lot of them are not well paid. If I hadn't of been a vet, I would have done a different career without animals where I earned more money and kept animals as a very in depth hobby. I'd then get the money AND the animal enjoyment without having to worry about the very low pay that animal jobs have to offer (normally below £20,000 which is nothing really). For me I would have ended up in some sort of scientific vocation e.g. lab work or something similar and then gone on from that route, and then do dog training, instructing and competing in my spare time. I'd have also needed to fund my sheep flock and horse obvs.
. I think that the danger with going down the zoology or animal science or behaviour route is that realistically, the job prospects aren't great, and even though it is nice too be able to work with animals, I think a lot of other factors have to come into it, unless you went on to do PHD, Doctorate etc.