feather eating and crop

Hi, one of my hens about 6 months old pinches the feathers from the bums of the others. They just tell her off and we know it is just a habit she developed at the place we got them from. They have a very "exciting" run with perches, branches and all manner of distractions. They have oyster shell and we are on sandy soil. This hen though has a massive crop, I'm going to check her again in the morning but I had a feel about 10ish this morning and it was already the size of a tennis ball and quite hot. I was just wondering if the feather eating would exasperate the problem. Hopefully she has just been a greedy whatsit, not looking forward to doing the upside down chuck massage thing. Nic

I was watching her today, mainly because we have some ex-bats mixing in with them and they have fewer feathers to start with! She wasn't doing it today but I think that it was because I took the fence down so there was a lot going on. 
The other hens just tell her off, but I've noticed that Fearnley who has the fluffiest bum has started to really give her a beating. My mate who is a vet nurse saw it for the first time at the weekend and reckons it's because the place they came from - although really clean and the guy loves his birds - was a bit sparse on distractions. He does feed them loads of veg and fruit which this particular hen is crazy about. I'm not so worried about the plucking and eating as most of the hens are super healthy and seem to be dealing with it. I just wondered if anyone knew if it contributed to the crop being impacted ( if it is )? Thanks, Nic

Well I grabbed her this morning and her crop was huge. Typically she is the only one who doesn't like being picked up and she's fast too. I've tried the oil and massage but was unsure how hard to do it. I've spoken to a poultry vet and she said quite firmly is ok. While I was waiting for her call I googled a bit and found some people have had success with maggots!!!!
As I can only get hold of her twice a day I thought it was worth a shot. Has anyone else tried this?
The vet seemed to think that she was probably ok as she's still laying and to keep massaging her for a week to 10 days. Nic.
P.S I think my friend can get me some antipecking spray.