Last solution is control on pet trade.
Suporting detalis3.1 : For example, not allowed to sell dogs that cause the problem of stray dogs.
Suporting detalis3.2 :"Under the relevant subsidiary regulations of the Public Health (Animals and
Birds) Ordinance, a person shall not carry on a business of selling animals (e.g. a pet shop)
without an “animal trader licence” (ATL) or maintaining an animal boarding establishment
(ABE — e.g. a pet hostel) without an “animal boarding establishment licence” (ABEL). As
at 30 November 2009, the AFCD issued a total of 155 ATLs and 25 ABELs (see Table 1 in
para. 1.3)."(OIE-Terrestrial Animal Health Code,2010,page13)