Can you give us a couple of more details?
An indiction of budget, what you would class as 'very close up' - is that just a photo of the eye only, or the whole head? Do you need the flexibility of a zoom or not?
As an idea, a canon 60mm macro is around £220 second hand, another £100 to buy new and will get you very close. A sigma 17-70mm zoom will be around the same price, and has more flexibility but won't get you as close in as the canon.
Plenty of other options as well
Mike
It will be mainly for head shots from a distance of probably no less than 12" - They are easily spooked and it'd be impossible to get head shots any closer
Price - Under £300 if possible?
What's wrong with using the 55-250?
You could get your headshots from a greater range with no need to spook the critters, & it'll cost you nothing![]()
Tamron 90mm macro!
True 1:1,sharp,great portrait lens aswell.
Easily in your budget s/h,might not be far off brand new?