I’ve found the eggs. The eggs are located inside the volcano in an amethyst cave. There are lava pools with groups of magmasaurs in them. There are small islands with craters in them, within those craters the eggs are nestled within. But be careful there are lots of magmasaurs, magma, and what look like varient rock elementals.
So after losses.. I've worked out the magmasaurs food drops at a rate of 15 (rounded up from around 13.7) per minute, 900 food per hour. Feed your mag 1 ambergris every half hour to keep a happy healthy lil magma blob
For those of you that are raising your very own magmasaur and are too afraid to get a good nights rest in fear of it starving to death. You’re in luck! If it has at least 2,000 food with some ambergris in its inventory/feeding trough. You can safely sleep for 6 hours with no worries.