Yes the feed if it is in pellet or crumble form does not need grit but the other treats you have been feeding her do require grit. Birds do not have teeth so they swallow small stones which go down their digestive tract with the food into a pouch called the gizzard. This is a very strong muscular organ with a tough lining that contracts to grind the little stones or grit with lumpy foods like grains and vegetation and insects to break them down so that it can be digested. The main feed has already been ground down and then reformed into pellets or crumbles which go to a mush inside the bird when it drinks water but the grains/corn and insects need there to be grit available for them to be processed. Over time the stones themselves get worn down to sand and passed out in their poop, so whilst your girl may have had some grit in her gizzard when you got her, she will almost certainly be in need of some now and that could mean she has a digestive impaction, so checking her crop in the morning will be quite relevant. She may also need some oyster shell or crushed up dried egg shells if you have not been supplying those either. The feed is a complete feed and contains enough calcium, but you have been diluting her intake of that by giving her extra treats which will almost certainly have less calcium content, so she may be becoming deficient in calcium which can also lead to egg binding. Hens can sense when they are deficient in grit or calcium and if you provide them in little separate dishes, they will eat what they need when they need it. Chicken grit can be bought relatively cheaply and even a small bag will last a very, very long time, but is essential to their digestive process if they are eating anything other than the formulated pellet or crumble.
Chicken nutrition is actually much more critical than many people realise. Hens have been selectively bred to be far more productive than nature intended, leghorns particularly so as one of the most prolific layers. Their bodies are operating at maximum capability and therefore like top level athletes, their bodies need a very carefully balanced diet. That complete formula feed is the product of some pretty serious scientific research. The reality is that it is designed to be fed as the only source of food, to provide the hen with everything she needs to stay healthy and produce eggs. Once you start throwing treats into the mix you begin to upset the balance of nutrients and over a period of time things can start to go wrong.
Don't get me wrong, a hens life would be pretty dull if all she ever had to eat was layer pellets or crumbles.... which is all most commercial hens get..... but it really is important to have a concept of how few treats can be given safely. I would reduce your meal worms to one tablespoon every other day at the most, maybe half an apple the next day, a tablespoon of cracked corn the day after. 2 or 3 green veggie leaves like spinach another day, perhaps a tiny bit of meat or fish or cottage cheese another day. No more than one tablespoon of one treat per day. Grit and oyster shell or egg shells are considered essentials, not treats because there is no real calorific value to them.
Hopefully that gives you an idea of where the line needs to be drawn. It will be tough to cut back but when you have done a necropsy on an obese hen that haemorrhaged and ruptured to death because she had been fed too much scratch, as I have, it provides a good mental image to deter you from being overly generous.
i think you should give her access to grit anyway
