One gosling left from four... advice needed!

Hi y'all, I live on a ranch and the ranch owners have 30 geese. They are all laying eggs- one mamma hatched four eggs and left the nest. The ranch owner asked me to take care of them, so I gladly said yes. She gave me some feed to feed them and a box and heating lamp and said I should be good to go. I feel so stupid for not looking further into it, but just thought everything would be fine because I thought she was experienced in this.
First days the goslings were healthy and happy. Grazing outside some and eating grass and bugs well. Then one of the baby's eyes started shutting or looking like the eye lids were stuck. Next morning it was dead. The next day another one died, it flipped around and flopped for awhile and finallydied. I thought it looked a as if it was poinsoned the way it's body and head was flopping The third did the same. I spoke to a vet and she said they were probably starving. The feed they had was some corn mash used to feed horses! And all they had was plain water to drink. Since that time I bought some chick starter feed and some electrolytes to put in water.
Last night when I got home from the store the last baby looked to be dying. Wouldn't move or eat. I forced some electrolyte water down her beak and also forced feed in its beak as well. Every hour last night I woke up and fed water and feed. It started to regain strength! Today it looks better but still hangs it's head and squeaks all the time. I have her under a heat lamp with availability to move to a cooler side. I have her nestled in a small towel she seems to like that. Her eyes are starting to get small and eyelids look sticky like the last ones. And it's face around its beak is getting sunk in a bit.
My question is- should I keep forcing water and feed to the baby? If so how often and how much should I feed and water it? Should I mash the feed with water?
It will now drink on its own but still won't eat. Any thoughts on how to convince it to eat? Or if it won't- what I should feed it other than chick starter?
Any other advice or ideas is helpful! Thank you so much! I really love these little goslings and so upset from my ignorance they died. I just pray I can get this last one healthy!

Oh my! I don't know geese very well--I Have ducks. Did you make sure to get UNMEDICATED chick feed? Geese naturally eat a lot of grass--Maybe try chopping up grass really fine, and seeing if it eats it?

You could also try chopping up the grass and putting it into the water dish. My ducks like to dabble for cut greens that way.

Make sure to keep the goose under the heatlamp--if geese are like ducks and chicks, they need to be warm!

Also, make sure that it has grit. You can buy it at the store (don't get the oyster grit, as that's birds that are already laying). I have sandy soil, so I just provide my ducks with a dish of soil, which gives them grit as well as some microorganisms in the soil.

I hope someone with more personal experience with geese chimes in!

*BUMP to the top for hopes of someone who has geese responding*

How's your gosling doing this morning?

I have two geese, but really don't know anything about them.  They just hang with the chickens and ducks and make noise.  Have not had any health issues to deal with.

Nicole is right to make note that the chick starter needs to be non-medicated.  Can't think of anything I would do that you are not already doing.  If the chick is still alive, then you might try moistening the chick starter with some of the electrolytes and maybe add a bit of molasses for energy.  Ducks and geese also need more niacin than chickens so if you have some capsules around for yourself you might open one and add that to a daily allotment of chick starter - though I doubt seriously that is a big issue this early on.

Good luck!

Now I've not owned geese, but I'm gearing up for it so I've been researching. Geese eat grass. No bugs, no corn, no sounds, no fish meal. Straight and simple vegetarians. They won't even harass your vegetable garden. I've read that the ground up chicken meal can be downright impossible for them to choke down. Their mouths are specifically formed to eat grass, not powder. Try providing a medley of grasses and see if that helps?