Can show what I'm doing for my indoor housing. Minimizing poop work is definitely a priority. It's possible there's a more efficient way, this is just what I came up with.
With what I am doing, I end up "straightening" cages and pens say, every 4th day or so. Maybe more often if it looks like it needs it. It depends on the cage's size and relative to size, how many animals are pooping and peeing in it, and so on.
Guinea pigs will demonstrate preferences on where they poop and pee in their pen if the environment is designed to support their natural bathroom habits. What I'm doing to minimize the amount of cleaning work I have to do is setting up the the cages with areas that they will naturally use as a bathroom, and making those areas able to be cleaned out quickly, without needing to reset the pen very often.
They like to poop and pee along tall walls and under things and in corners. So, my big pens have the floors that are next to tall, solid walls and including corners set up as a litterbox zone that is straightforward to clear out and replace the bedding in.
The pen is constructed of wood. Above that, a relatively permanent plastic cover that runs partway up the walls is cut and installed. Above that is one layer of towel material. Then sitting above that is the portion of the floor that the guinea pigs touch. There is a piece of thin fleece blanket that has deliberately been laundered/machine-dried at too high a temperature and generally lets liquid pass through it (the older it gets the better it gets at this). That fleece is all the way across the floor and partway up the walls. On top of that, there is a plastic liner - one piece - that is cut to the exact right shape that goes along the back and sides of the pen. Then, small-diameter circular wooden dowels are taped into place to create that whole back and side area as the litterbox area. You want small diameter dowels, like 1cm or something, because guinea pigs have short legs and you want to minimize the chance/damage from them smacking their feet into the dowels. You want the circular ones, not square.
All of this stuff is secured with a high quality clear packing tape sort of tape.
The point of all that trouble is that you don't have to reset the cage for a long time. You just scoop out the litterbox areas. The purpose of the towels is to help absorb the pee when they do decide to just pee outside the litterbox area for some reason.
When the cage needs to be completely reset because the fleece and the towels underneath are just too nasty and/or they tore up the plastic litterbox liner in spots and you want to replace it, it is a significant amount of work.
Having said that, the point is that you don't need to reset often. If you have the design matching what they want to do, they won't pee outside of the litterbox area very often. The pee is a bigger deal than the poop, although you can't let the poop just pile up, it's not good for their health and skin/feet to have anything nasty pile up.
Some pics:
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Above is a view of a pen before being straightened.
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Above is a view when I just finished removing all the nasty. I removed the 2 lowest ranking animals before starting so things would stay calm as I did the work. They tend to crowd together when I'm doing this and they can get all pissy if the wrong combination of animals gets bunched up like that.
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Above is the pen with the pellets replaced and the animals put back in. You don't want a dense layer of pellets because they expand when they get wet and then tons of them spill out of the litterbox and everything gets stupid.
Note the partially-visible empty bowl to the bottom right. There is a water bottle mounted above that bowl. Guinea pigs can be messy drinkers and it's best to put a heavy bowl under the bottle + keep the water bottle in the litterbox area (both things). Some make a bigger mess than others but all it takes is one messy drinker to turn the pellets under the bottle to mush or soak whatever is under there.
It's possible to scrub down the plastic area with a weak bleach solution if you think it's best, but you'll want to remove all the animals while you are doing that, because fumes.
Some of my cages at this time are the more typical pet type. They are done a bit like the above, but in miniature.
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Just finished cleaning up the nasty in pic above. The "ends" of the cage are set as litterbox areas. This cage has no dowels because it's being used for recuperation of a sick guinea pig + a breeding cage (they run around while breeding and anything that can obstruct their feet while they are running is bad). With this cage there is no need for the permanent-ish layer of plastic at the very bottom because it is a plastic container, not a wood pen.
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Above is Wilbur and Mousey in the newly straightened cage. This cage has no little house area or toys or such because those objects are in the way for breeding animals. When using a cage that should not utilize little housing areas directly in the cage for some reason, you can drape a towel over one side of the cage, thereby creating an enclosed area without having an obstruction within the cage. This cage in essence has 2 places for them to feel like they can be "in" something - directly under that hay rack to the top right. and the left 1/3rd gets towel-covered.
The bowls and such are in the middle, not on the sides, because guinea pigs perceive the sides of areas, like next to walls, to be travel areas. So, you want the sides to be clear of obstructions such as food bowls and toys that do not allow direct passage through.
I got the plastic sheeting at a hardware store. It comes in omg-huge rolls that are so big that the sheets are folded in 2 as they are wrapped onto the spindle. The permanent layer on the bottom of the big pen uses it folded as it came, essentially 2 layers. There were 2 kinds of plastic available, one that was supposedly resistant to steam and one not. I got the steam resistant one.
You may have seen pictures of guinea pigs housed on hardware cloth flooring. Some of the pictures of this I have seen are from cuy being kept in South America, ie: not USA or UK. Assuming you are living in USA or UK, you do not want to do your animals like that for 2 reasons.
Reason 1:
Paragraph below is quoted from book The Biology of the Guinea Pig, bottom of page 7 into page 8:
Several articles, particularly in the British literature, describe the successful use of wire floor cages in guinea pig breeding colonies. Therefore a room of wire-bottom cages was designed and installed in the Fort Detrick breeding colony to test the desirability of wire floor cages verses solid floor cages. Two hundred females were maintained in this room for 3 years of testing. From almost every aspect, the use of wire-bottom cages in this breeding colony was unsatisfactory. The production rate was 22% below that of the colony on solid-bottom cages and the young weighed 25% less at weaning. Bacterial pneumonia was the principle cause of a higher mortality rate among both adults and offspring. Other guinea pigs had to be eliminated because of emaciation and debility. The wire mesh floor was essentially devoid of sharp projections yet many animals had to be culled because of pododermatitis. Hairlessness increased significantly in this colony, and guinea pigs turned a dirty rust color on their ventral surfaces. Many young were caught in the wire mesh, suffered fractured legs, and had to be destroyed.
They ultimately concluded that wire cages using really small wire mesh may have advantages for short-term stuff, but it's no good for long-term housing such as breeding colonies.
Reason 2:
As a guinea pig breeder, there are piles of people (in particular in USA and UK) who look down upon you or even hate you. They will use the derogatory term "backyard breeder" to describe you. If they are aware that you are breeding guinea pigs (especially high-ish volume) and can identify you, plus you're not one of their purebred-breeder
dandy friends, they will report you to your local animal welfare authority for abusing animals.
It doesn't matter if you are not abusing animals. It doesn't matter that your husbandry may outclass theirs. They won't try to verify anything themselves. They will report you because they can; because breeding guinea pigs is evil and they dislike/hate you that much.
After they report you, the local animal welfare authority people will show up at your door unannounced, wanting to see your animals. The people who show up may already be biased against you. There was a complaint about you, after all. They may very well believe the anti-guinea-pig-breeder hatred pseudo-science spew that is floating around the internet right now. They may have already labeled you as a simpleton "backyard breeder" who should probably give up animals and walk away in shame and go repair rusted cars on your lawn instead.
If they find your guinea pigs in wire floor cages, they might take action against you, such as maybe taking your animals.
Considering the description from the study above, it's hard to argue that wire floors represent good care. They sound like the lazy way to go, demonstrating the minimal possible regard for the animals' comfort, health, and safety. We don't live in third-world countries and we don't need to go with wire floor cages.