Our boys do the same... I cant open a bag of chips without them thinking Its food or Timothy hay for them!
Speaking of hay, I found the perfect solution to all the hay mess I used to have. I started buying the Timothy Hay pellets made for horses in 40 (or is it 50) lb bags. I would pour them into a Rubbermaid bin to store them and 1 bag would last a LONG time, not to mention the cost was a small fraction of what I was paying in the pet stores for small bags of hay.
The hay pellets are hard enough that they help the pigs keep their teeth nicely worn so they don't end up with over-grown teeth. Piggies can not eat much Alfalfa so no
mixed pellets, ONLY Timothy or Orchard pellets can be used for the piggies.
One important tip about the health of guinea pigs is to be sure to ONLY use bedding with no tree oils, especially pine. Aspen was a good one to use or Carefresh bedding, but Aspen was less expensive.
Most piggies that die under age 4 is usually due to improper nutrition. Every piggy I had lived for 6 or more years with me, even the shelter piggies that I had no idea how old they were to begin with. If you feed them the proper foods and give them the space they need, they can live from 4 to 8 years old.
Let's stop talking about piggies before I end up going to the shelter to save a few more .....