A lot of deer will be dying off naturally around this time of year, old and young. Also, it might not have been that particular dog but there are loads of pet dogs big enough to take down a deer (depending on the species of deer) in the UK. One of my childhood dogs was a Deerhound cross Lurcher and he took down a few.
What did you do when this happened?
Been wondering for a while what the legal ramifications are as my dog like many others does chase them, but she’s a collie and getting on a bit now so can’t get near them, but it is one of those things that makes you a bit paranoid.
I think you can be prosecuted under the dangerous dogs act (or something like that) and given there are a lot of people about who’d want you prosecuted for even wearing the wrong type of wellies I think a deer kill is something you’d be in serious bother for.