Welcome to the forum
- How old are they?
- How long have you had them?
- Have you checked yourself that they are both definitely female? (Standard question to ask where the piggies are new and/or came from a pet shop or breeder)
Rumbling is a totally normal dominance and communication behaviour for all piggies. They do it to establish/reestablish and maintain their bond and hierarchy. There is no need to do anything (nor should you do anything) to stop it.
They do it more when they move to a new environment (which is why you saw it more when You first got them) but also sows will do it when they are in season, which occurs around every 15-17 days. A strong season will produce stronger behaviours but spaying won’t help as spayed sows will still rumble frequently given it is a method of communication and dominance.
Also spaying is a major surgery so usually only done if there is a medical need for it ie ovarian or uterine problems such as cancers, infections or cysts.
You should never separate them for this behaviour. Separating them won’t help and in fact will cause even more dominance behaviours when you reintroduce them as they will have an increased period of reestablishing their bond.
Also:
- if you separate and reintroduce too often you can actually harm their bond and cause them to refuse to go back together, plus separation causes them stress particularly if they are babies (whom should never be alone).
- separate them for too long at a time, and you then you have to go through the full neutral territory reintroduction process (ie you cannot just put them back into the cage together) - to check they will go back together and to help stop any territorial issues occurring (if one then sees the cage as their own territory due to having been apart for too long then that piggy can then refuse to allow the other back in)
The only time you separate is where the bond is suspected of failing/has failed - defined by the presence of specific behaviours such as complete refusal to interact or increasingly acrimonious face offs and relentless and aggressive chasing and/or bullying, or actual fights (although actual fights in incompatible sows, while they can happen, are less common than with incompatible boars).
There are ways and means to test the functionality of a bond (which is a several day trial separation and one time neutral reintroduction) but ultimately if piggies are incompatible the bond will fail and they would need to be permanently separated and live in two cages side by side from then on.
How big is their cage?
Two storey cages aren’t how piggies like to live. They are ground roaming animals who need their space to be big enough on a single ground level.
A two storey cage also does not count towards floor space - only the bottom level counts as cage size (an upper level doesn’t double it) so if that bottom level isn’t big enough then it means they don’t have enough room.
For two sows you need a minimum of 120x60cm on a single level but we recommend a cage of 150x60cm (or a 4 grid by 2 grid c&c) to ensure they really do have enough room (120x60cm while it is welfare minimum, doesn’t always provide enough space).
All hides must have two exits.
Any single exit hides should be removed as they can mean one piggy can get trapped inside by the other and is a flashpoint for issues
We do not recommend the use of food bowls. Instead we recommend that their one cup of veg each and one tablespoon of pellets each are scattered all around the cage and in hay. That way th dominant piggy cannot food hog but importantly it encourages them to forage. Foraging is how they spend the majority of their time, it keeps them occupied and mentally stimulated whereas sat eating at a bowl is tether mindless and removes all mental stimulation for them.
Hay is the most important part of daily food intake anyway, so if one day one piggy gets more veg than the other other, then it will even itself the next day.
You ensure they are eating adequate hay via the routine weekly weight checks.
I’ve added guides below which explain everything I’ve mentioned in more detail
I hope that helps. We are more than happy to answer any questions you may have
Sows: Behaviour and Female Health Problems (including mounting and ovarian cysts)
Dominance Behaviours In Guinea Pigs
Guinea Pig Behaviours in their Context
Cage Size Guide
Bonds In Trouble
Bonding and Interaction: Illustrated Bonding Dynamics and Behaviours
