Internal trauma is very likely a cause of that lump, if it is indeed an egg. Having seen membranous eggs being laid is another often related sign. So it could be a side effect of the fox/raccoon attack. Doesn't sound like worms, doesn't really look like it either to me, but worming is a good thing to maintain because some worms are not readily obvious but can do permanent damage. (Like rat lungworm passing into dogs through rat feces having been eaten by a slug or snail which is then eaten by the dog, and then causing severe and often fatal neurological symptoms in the dogs).
Chooks need worming like any other animal if restrained from accessing the natural methods of self-worming and parasite control. Most animals, even those domesticated for millions of generations, retain some instinct regarding how to worm themselves and remove internal and external parasites. Chooks do it through consuming certain plants and dust-bathing.
If you use chemical wormers then you can't eat the eggs for a while. Personally I don't use artificial stuff, because it's a bit like bashing the whole animal to kill a flea. I use various things to maintain their health and some of these are a staple or regular occurrence in their diet which prevents parasites from establishing colonies or surviving on these hosts. The additional worming I do seems useless because they're already worm-free but I maintain anyway, just in case. I use wholemeal bread, and put tabasco sauce on every slice, chop/rip it up into small bits (so they don't have to battle with it and potentially get some in their eyes) and feed it to them, once a month, average, when the moon is a few days off being full. This is the time when worm species of many sorts travel from the organs into the digestive tract to reproduce. This means they're being burned alive by the hot food. It also damages their eggs and therefore has a wide spectrum range of usage.
Chooks love hot foods, don't worry about burning them. I usually give them cayenne and black pepper and garlic and onion etc as a regular feed addition. It does cost more than just plain pellets, but these chooks are providing eggs and meat for my family's health's sakes, so if it costs more to be that healthy, then so be it. We've grown to really dislike the eggs and meat grown on pellets/crumble and artificial meds, once you go home-grown you can't go back, it tastes horrible. We grow organic for health reasons.
We get plain fermented chilli tabasco here, no sugar or other stuff, but just as often I use plain cayenne or chilli powder mixed with yogurt on bread. It all works and the cayenne/chilli will also be helping increase circulation, reduce inflammations, and strengthen their heart etc. Dairy and sugar are beloved of parasitic worms, in fact you could call them worm food or bait. When worming the little kids we do the same. Hot stuff, mixed with raw sugar (or honey) and dairy.
I feed the chooks various herbs pretty much as a staple in their diet, like rosemary, sage, nettle, etc and also kelp is a definite staple. But a very important thing to do to control most diseases and all parasites is constant raw fresh garlic. It contains natural sulfur compounds which build up to a stable level in the animal's tissues and bloodstream. This level of sulfur helps the chooks heal quicker and renders them basically immune to parasites because it's toxic to such tiny creatures.
It is not an irregular-feed efficient addition to the diet, if you only give them garlic once a month it won't protect them. People will tell you it's toxic and fatal to give the Allium family to chooks but it is not. The studies 'proving' that were shamelessly dishonest and biased, commissioned because garlic presented a competitive threat to some commercial industries who were manufacturing refined or artificial sulfur alternatives, which are unfortunately harmful. The initial industrial interest in sulfur compounds for heath usage was spurred by investigation into why garlic helps heal. You would literally need to force feed a chook garlic for months to kill it. And nothing else, just garlic. And then it would die through lack of other dietary nutrients before it died of overly high sulfur levels, really. I let my chooks eat as much as they want quite often. I've had sick chooks elect to eat nothing but garlic for weeks and they recovered from their ailment.
A fast followed by garlic is the cure for many diseases of poultry. But Rue is supposed to be even better than garlic for chooks. I recommend you try a book by Juliette de Bairacli Levy called 'The Herbal Handbook for Farm and Stable' as it gives a great introduction into using herbs to treat animals. I was skeptical about a lot of it, but tested extensively, and it's a life saver. She gets flack for saying to dust chooks with tobacco dust to get rid of mites/lice, but back when that book was written, tobacco was just the plain plant, not the chemicalized stuff people smoke nowadays. Old book but worth getting. Can be found online. She was a strange one, but the info she collected from ancient lore of many countries on treating diseases naturally, is invaluable. It works.
