The largest part of their diet needs to be hay - it should be available in large amounts at all times.
I personally don’t use hay racks as my boys enjoy being in amongst large loose piles of hay, they play in it etc and eat so much more without the restriction of a hay rack.
I also don’t use bowls - being boars, it’s important to never give them a reason to bicker so I scatter feed all veg so the dominant cannot food hog. It also provides enrichment as they have to search for it in amongst their hay piles.
Veg and pellets are supplementary and jointly only make around 20% of the daily food intake. They should not be filling up veg and definitely never on pellets.
Veg is about one cup of veg per pig per day, ensuring a variety including high vitamin c veggies such as coriander or bell pepper. High calcium veggies such as spinach, kale and parsley kept to a small amount and only once a week. High sugar items such as fruit or carrot kept as a very occasional treat. Cabbage can cause bloating so best to only feed small amounts occasionally.
Daily veggies for my boys are lettuce, coriander and another herb, cucumber, bell pepper and usually a green bean. Other items as added in at times for variety. I do tend to feed a little more than a cup of veg per day though (along with fresh grass) but my boys don’t get pellets often and get dried forage instead.
The important thing to note is that any new veg needs to be introduced slowly so as to not cause an upset tummy.
Pellets are strictly one tablespoon per pig per day. Pellets are the least healthy part of the diet and contribute a lot of calcium to the diet. Too much calcium isn’t good for them - although too little also isn’t good. If you ensure pellefs are kept limited and their drinking water is filtered, then that can help to get a balance of ensuring they get some but not lots of calcium
The guide below will help further
Long Term Balanced General And Special Needs Guinea Pig Diets
Edible And Forbidden Veg And Fruit List With Vitamin C Grading
The way to know they are getting enough hay is via the weekly weight checks (switching to daily weight checks whenever there are health concerns). Any drops in weight (beyond normal fluctuation) and it can mean their hay intake has reduced (and then you need to step in with support feeding and vet care). You cannot tell they are eating enough hay by watching them eat it
Weight - Monitoring and Management
