What has the EU ever done for our animals?
While the economy, immigration and sovereignty take centre stage in the referendum debate, here's a look at EU issues relevant to those concerned about animals and their welfare:
Ban on cosmetics tested on animals
"Animal suffering just for cosmetics reasons" has been outlawed in all EU member states since 2013, blocking companies testing toiletries and make-up on animals from a market of 500 million people across 28 countries.
It seems unlikely the UK would back out of the ban Britain if it voted to leave the EU, and some feel the regulations are not strict enough, but this level of multi-national cooperation is an example of how the EU can use its combined might to improve animal welfare.
"Five Freedoms" for farmed animals
Promoting and protecting the welfare of farm animals has steadily grown over the EU in the past four decades, particularly in the European Convention for the Protection of Animals kept for Farming Purposes.
This enshrines "Five Freedoms" for the protection of animals kept for the production of food, wool, skin or fur, or for other farming purposes, including fish, reptiles and amphibians.
The Five Freedoms are:
:: Freedom from hunger and thirst
:: Freedom from discomfort
:: Freedom from pain, injury and disease
:: Freedom to express normal behaviour
:: Freedom from fear and distress
While vegetarians are against animal slaughter completely, and vegans rule out animal farming entirely, many welcome improvements in animal welfare as a positive step forward - as do those who eat meat, but want to see suffering reduced.
Farming subsidies and blood sports
One of the unfortunate quirks of the EU's Common Agricultural Policy for animal rights campaigners is the fact that those managing areas for blood sports such as grouse shooting, salmon fishing and deer stalking are entitled to claim EU farming subsidies.
With concerns over animal suffering, the impact on wildlife, and alleged illegal animal poisonings and trappings linked to shooting estates, this is one of the more unpopular aspects of EU policy for those concerned about animal welfare.
Battery hens, crates and cages
While many are still unhappy with the conditions in which farmed animals are kept, the EU has introduced bans on veal crates (2007), battery cages (2012) and sow stalls (2013).
Again, it seems unlikely the UK would automatically rescind these rules in a Brexit scenario, and some organisations have bemoaned Brussels for not strictly enforcing the regulations, but it is another example of nations standing in solidarity to change farming practices across all member states.
When the Lisbon Treaty came into force in 2009 it introduced the recognition that animals are sentient beings.
Article 13 of Title II states that the EU and its member states "since animals are sentient beings, pay full regard to the welfare requirements of animals".
However, it does go on to say this must respect "legislative or administrative provisions and customs of the member states relating in particular to religious rites, cultural traditions and regional heritage," leaving room for practices which some may find as causing suffering to farmed animals.
Taking your pets to other EU countries
The EU has harmonised rules on travelling with pets, making it easier for its citizens to move freely with their companion animals with the Union.
Dogs, cats and ferrets are susceptible to rabies, but proof of vaccination against the disease in a pet passport or animal health certificate is all they need to travel across EU borders, with certain exceptions. The rules apply to non-commercial movement only, not for those importing and exporting pets for sale.
Non-EU countries have stricter rules for bringing pets into EU member states, so the UK could potentially lose this benefit if it left the Union.
Animal rights organisations let out a giant "we won!" last year when MEPs approved an amendment to the 2016 budget stating no EU money should be used to fund "lethal bullfighting activities" - a cut worth about £110million.
But the move has been described as "unenforceable".
The EU does not give any agricultural money specifically for bullfighting. However, it does not have the power to prevent subsidies finding their way to the industry.
Spanish farmers still receive direct payments under the Common Agricultural Policy (CAP), and these are granted per eligible hectare of land, not on what or how much they produce.
The EU has no legal power to stop Spanish farmers using CAP subsidies to raise and sell bulls which ultimately end up being used for bullfighting. It's a matter for Spanish national law.
One of the more controversial aspects of EU activities, the Common Fisheries Policy is often blamed for mismanaging Europe’s highly productive seas and "giving away our fish”.
However, Friends of the Earth (FOE) has reported that since EU policy was reformed in 2002, the health of many fish populations has improved - with North Sea cod, once synonymous with over-fishing, now recovering strongly.
The EU is now phasing out the discarding of unwanted fish, a practice which was very publicly maligned in a campaign and television programmes by celebrity foodie Hugh Fearnley-Whittingstall's, and setting quotas more in line with scientific advice.
While vegetarians and vegans do not eat fish and many disapprove of commercial fishing practices, some may be comforted to know marine populations are being less threatened under new policies.
Friends of the Earth (FOE) has issued a warning about bee populations, fearing EU nature directives - which have been vital for helping Britain's bees - would cease to apply.
FOE said EU nature rules have been vital for protecting the places bees live and the flowers they feed upon.
It cites UK Government's move to allow the use of banned pesticides, despite growing scientific evidence of their harm, as evidence of Britain's leaders failure to act alone in the best interests of bee populations.
FOE said: "Bees are vital for pollinating our food and wildflowers, including British strawberries and apples. Leaving the EU is a risk to these important insects."