Ah my area of knowledge. Not by choice, just for some reason I've had numerous chooks suffer with crop problems.
I doubt much is getting through if she does have crop problems.
Firstly can I ask why you are afraid to massage her crop and turn her upside down to squeeze it out? If its because you've never done it before I can talk you through all the steps and with two people it can be done well enough. You just need to be confident and follow it all carefully. Check with your vet about the cost before hand and see how much they charge. I opted to do this as a last resort as my hen was on chicks but alas although I had it done she still grew weaker and we felt that she had problems further down also.
Also I don't know where you get the idea having her crop snipped open will cost a fortune in vets bills. Its a really simply procedure (and doesn't require a lot of anaesthetic if any at all) and last time my vet did the procedure it cost me £32 total for the op. I dropped her off around lunchtime and picked her up at 5pm. A few stiches and you'd never know she'd had her crop cut open.
If her crop is impacted (and it sounds to me like its this, not sour crop) it will mean there is actually a blockage and therefore food is only getting through in small amounts. Eventually she will probably develop a secondary infection on top of this, usually if the foods ferments and sour crop or other nasty stuff sets in. Or else she will develop something nasty within her system. Once that happens because of her weakend state she probably won't pull through.
Impacted crop can be best treated by having the crop cut open and the contents removed and then being very careful for at least 2 weeks with what she is eating, ie easily digestable, small food, not hard stuff. I feed chick crumb, ready break, a bit of live yogurt and things like that. Then gradually introduce other foods back into the diet.
If cutting the crop open isn't an option then syringing down a bit of olive oil, massaging it gently but firmly and then mix down a bit of water also, massage again before turning her upside down and empying the crop. If you want to know how to do this I can write another post later to explain how. All being well with this process you can empty the crop of its contents and repeat it 12 hours later to ensure its empty.
You can also have some antibiotics injected (better than orally) by the vet and this should help prevent any nastiness. But you need to empty the crop also as one without the other is pointless.
If you don't do one or the other if it is impacted then chances are you will loose your hen. Sorry to be so blunt but there usually isn't a pretty end to this sort of thing. And if regular massage on its own hasn't worked then you are running out of options.
With regards to the egg laying problem does she have oyster shell in her diet?
Anyways, let me know whats what and I am more than happy to write a post to explain how to empty a chickens crop of its contents.