They probably aren't getting enough protein.
Your pellet feed is 15% which is the bare minimum IMO, and then the other feed is only 10% I think it is equivilent to "scratch grains" so if you mix it half and half your protein is actually only 12%.
The third food you listed looks like good pet food, and it is 17% protein which is nice. I understood that this is a temporary thing, they haven't been on this feed long because it's just "leftover" from another pet?
Adding all the table scraps especially bread will further reduce their protein intake.
I feed my chickens 20% protein feed, especially because I raise mainly heavier breeds (dual purpose breeds). I think it's better for them to get a little extra than not enough, but I know that others do disagree. Eggs are mainly made up of protein so having at least 16% is important for egg production, and then there is always their day to day needs for their bodies besides just what they put into the eggs. I do know that if they are eating feathers it is because they are not getting enough protein so I would definitely get something like 18% grower feed, or 20% gamebird feed, and stop feeding the second feed that you listed.