become an expert
https://www.cambridge.org/gb/files/3214/7610/6092/Liability_for_Animals_Mulheron.pdf
The current statute is Animals Act 1971 - I am not barmaid but just a litering hanger on - and huge case law
This is mainly about dogs and horses squashing and biting humans
The nerest to you would be - marauding dogs and negligence comes into that - and you say yo have been careful
next head is contract - you have signed a care contract and is there an obvious clause about bonking botches?
Standard of care is decided by negligence
the third head is negligence and see Chris effort
BUT - what is the damage - or financial loss ? none as far as I can see
no damage no case
that too is whether you have taken care which you say you have
and also - - - whether they told you the dog was in season
[my own guess is they actively didnt in case you said oops no go and then ..... they cdnt go on holiday]