A lot of people like to offer their birds cooked mash or food made from boiled, steamed, microwaved or baked vegetables, & most birds thoroughly enjoy having this as an evening meal.
Cooked mash is not a highly nutritious food. Once the veggies are boiled, microwaved, steamed or cooked in any other way they can lose a lot of their nutritional value, even if they’re steamed lightly.
Carrots are an acceptation. You need to cook carrot to release the carotenes. Carrots block cancer and lowers cholesterol. Raw carrot is very high in vitamin A.
Parrots who are hormonal should not be offered mash. Offering mash can encourage hormonal behaviours as well as destructive and behavioural problems. When they’re breeding they offer each other regurgitated food which is warm and mushy. Offering mash is similar to this so it can cause problems.
As an alternative to cooking the veggies you can grate them. This will retain the nutritional value & it won’t be a mash, there will still be the crunch to it. You can also add a cooked egg and shell to it.
You can also make bird friendly recipes every now and then. Most birds do enjoy this & recipes can be found anywhere on the internet.
Cooked food or mash is not a natural food for them so it won’t hurt them to never have it. If you do offer it try and make it on an occasion only and not on a regular basis.